diff --git a/npm_and_yarn/lib/dependabot/npm_and_yarn/update_checker.rb b/npm_and_yarn/lib/dependabot/npm_and_yarn/update_checker.rb
index 8b813959f9..a3da496044 100644
--- a/npm_and_yarn/lib/dependabot/npm_and_yarn/update_checker.rb
+++ b/npm_and_yarn/lib/dependabot/npm_and_yarn/update_checker.rb
@@ -375,7 +375,11 @@ def library?
         return true if dependency_files.any? { |f| f.name == "lerna.json" }
 
         @library =
-          LibraryDetector.new(package_json_file: package_json).library?
+          LibraryDetector.new(
+            package_json_file: package_json,
+            credentials: credentials,
+            dependency_files: dependency_files
+          ).library?
       end
 
       def dependency_source_details
diff --git a/npm_and_yarn/lib/dependabot/npm_and_yarn/update_checker/library_detector.rb b/npm_and_yarn/lib/dependabot/npm_and_yarn/update_checker/library_detector.rb
index 6244797e63..3f39cb5668 100644
--- a/npm_and_yarn/lib/dependabot/npm_and_yarn/update_checker/library_detector.rb
+++ b/npm_and_yarn/lib/dependabot/npm_and_yarn/update_checker/library_detector.rb
@@ -8,8 +8,10 @@ module Dependabot
   module NpmAndYarn
     class UpdateChecker
       class LibraryDetector
-        def initialize(package_json_file:)
+        def initialize(package_json_file:, credentials:, dependency_files:)
           @package_json_file = package_json_file
+          @credentials = credentials
+          @dependency_files = dependency_files
         end
 
         def library?
@@ -20,7 +22,7 @@ def library?
 
         private
 
-        attr_reader :package_json_file
+        attr_reader :package_json_file, :credentials, :dependency_files
 
         def package_json_may_be_for_library?
           return false unless project_name
@@ -36,7 +38,8 @@ def npm_response_matches_package_json?
           return false unless project_description
 
           # Check if the project is listed on npm. If it is, it's a library
-          @project_npm_response ||= Dependabot::RegistryClient.get(url: "https://registry.npmjs.org/#{escaped_project_name}")
+          url = "#{registry.chomp('/')}/#{escaped_project_name}"
+          @project_npm_response ||= Dependabot::RegistryClient.get(url: url)
           return false unless @project_npm_response.status == 200
 
           @project_npm_response.body.force_encoding("UTF-8").encode.
@@ -56,6 +59,15 @@ def escaped_project_name
         def parsed_package_json
           @parsed_package_json ||= JSON.parse(package_json_file.content)
         end
+
+        def registry
+          NpmAndYarn::UpdateChecker::RegistryFinder.new(
+            dependency: nil,
+            credentials: credentials,
+            npmrc_file: dependency_files.find { |f| f.name.end_with?(".npmrc") },
+            yarnrc_file: dependency_files.find { |f| f.name.end_with?(".yarnrc") }
+          ).registry_from_rc(project_name)
+        end
       end
     end
   end
diff --git a/npm_and_yarn/lib/dependabot/npm_and_yarn/update_checker/registry_finder.rb b/npm_and_yarn/lib/dependabot/npm_and_yarn/update_checker/registry_finder.rb
index 90deb85b94..9faaa6152c 100644
--- a/npm_and_yarn/lib/dependabot/npm_and_yarn/update_checker/registry_finder.rb
+++ b/npm_and_yarn/lib/dependabot/npm_and_yarn/update_checker/registry_finder.rb
@@ -19,6 +19,10 @@ class RegistryFinder
           /^registry\s*=\s*['"]?(?<registry>.*?)['"]?$/.freeze
         YARN_GLOBAL_REGISTRY_REGEX =
           /^(?:--)?registry\s+['"](?<registry>.*)['"]/.freeze
+        NPM_SCOPED_REGISTRY_REGEX =
+          /^(?<scope>@[^:]+)\s*:registry\s*=\s*['"]?(?<registry>.*?)['"]?$/.freeze
+        YARN_SCOPED_REGISTRY_REGEX =
+          /['"](?<scope>@[^:]+):registry['"]\s['"](?<registry>.*)['"]/.freeze
 
         def initialize(dependency:, credentials:, npmrc_file: nil,
                        yarnrc_file: nil)
@@ -46,6 +50,13 @@ def self.central_registry?(registry)
           end
         end
 
+        def registry_from_rc(dependency_name)
+          return global_registry unless dependency_name.start_with?("@") && dependency_name.include?("/")
+
+          scope = dependency_name.split("/").first
+          scoped_registry(scope)
+        end
+
         private
 
         attr_reader :dependency, :credentials, :npmrc_file, :yarnrc_file
@@ -64,7 +75,7 @@ def first_registry_with_dependency_details
               nil
             end&.fetch("registry")
 
-          @first_registry_with_dependency_details ||= global_registry
+          @first_registry_with_dependency_details ||= global_registry.sub(%r{/+$}, "").sub(%r{^.*?//}, "")
         end
 
         def registry_url
@@ -194,22 +205,32 @@ def global_registry
           npmrc_file&.content.to_s.scan(NPM_GLOBAL_REGISTRY_REGEX) do
             next if Regexp.last_match[:registry].include?("${")
 
-            registry = Regexp.last_match[:registry].strip.
-                       sub(%r{/+$}, "").
-                       sub(%r{^.*?//}, "")
-            return registry
+            return Regexp.last_match[:registry].strip
           end
 
           yarnrc_file&.content.to_s.scan(YARN_GLOBAL_REGISTRY_REGEX) do
             next if Regexp.last_match[:registry].include?("${")
 
-            registry = Regexp.last_match[:registry].strip.
-                       sub(%r{/+$}, "").
-                       sub(%r{^.*?//}, "")
-            return registry
+            return Regexp.last_match[:registry].strip
+          end
+
+          "https://registry.npmjs.org"
+        end
+
+        def scoped_registry(scope)
+          npmrc_file&.content.to_s.scan(NPM_SCOPED_REGISTRY_REGEX) do
+            next if Regexp.last_match[:registry].include?("${") || Regexp.last_match[:scope] != scope
+
+            return Regexp.last_match[:registry].strip
+          end
+
+          yarnrc_file&.content.to_s.scan(YARN_SCOPED_REGISTRY_REGEX) do
+            next if Regexp.last_match[:registry].include?("${") || Regexp.last_match[:scope] != scope
+
+            return Regexp.last_match[:registry].strip
           end
 
-          "registry.npmjs.org"
+          global_registry
         end
 
         # npm registries expect slashes to be escaped
diff --git a/npm_and_yarn/spec/dependabot/npm_and_yarn/update_checker/library_detector_spec.rb b/npm_and_yarn/spec/dependabot/npm_and_yarn/update_checker/library_detector_spec.rb
index 1e2472a4c5..136bbb8101 100644
--- a/npm_and_yarn/spec/dependabot/npm_and_yarn/update_checker/library_detector_spec.rb
+++ b/npm_and_yarn/spec/dependabot/npm_and_yarn/update_checker/library_detector_spec.rb
@@ -5,10 +5,18 @@
 require "dependabot/npm_and_yarn/update_checker/library_detector"
 
 RSpec.describe Dependabot::NpmAndYarn::UpdateChecker::LibraryDetector do
-  subject(:finder) { described_class.new(package_json_file: package_json_file) }
+  subject(:finder) do
+    described_class.new(
+      package_json_file: package_json_file,
+      credentials: credentials,
+      dependency_files: dependency_files
+    )
+  end
   let(:package_json_file) do
     project_dependency_files(project_name).find { |f| f.name == "package.json" }
   end
+  let(:credentials) { {} }
+  let(:dependency_files) { project_dependency_files(project_name) }
 
   describe "library?" do
     subject { finder.library? }
@@ -64,5 +72,69 @@
         end
       end
     end
+
+    context "with a custom global registry" do
+      let(:project_name) { "npm8/library_with_global_registry" }
+
+      context "not listed in registry" do
+        before do
+          stub_request(:get, "http://example.com/dependabot/etag").
+            to_return(status: 404)
+        end
+
+        it { is_expected.to eq(false) }
+      end
+
+      context "listed on registry" do
+        before do
+          stub_request(:get, "http://example.com/dependabot/etag").
+            to_return(status: 200, body: body)
+        end
+
+        context "with a description that matches" do
+          let(:body) { fixture("npm_responses", "etag.json") }
+          it { is_expected.to eq(true) }
+        end
+
+        context "with a description that doesn't match" do
+          let(:body) do
+            fixture("npm_responses", "is_number.json")
+          end
+          it { is_expected.to eq(false) }
+        end
+      end
+    end
+
+    context "with a custom scoped registry" do
+      let(:project_name) { "npm8/library_with_scoped_registry" }
+
+      context "not listed in registry" do
+        before do
+          stub_request(:get, "http://example.com/dependabot/@dependabot%2Fetag").
+            to_return(status: 404)
+        end
+
+        it { is_expected.to eq(false) }
+      end
+
+      context "listed on registry" do
+        before do
+          stub_request(:get, "http://example.com/dependabot/@dependabot%2Fetag").
+            to_return(status: 200, body: body)
+        end
+
+        context "with a description that matches" do
+          let(:body) { fixture("npm_responses", "etag.json") }
+          it { is_expected.to eq(true) }
+        end
+
+        context "with a description that doesn't match" do
+          let(:body) do
+            fixture("npm_responses", "is_number.json")
+          end
+          it { is_expected.to eq(false) }
+        end
+      end
+    end
   end
 end
diff --git a/npm_and_yarn/spec/dependabot/npm_and_yarn/update_checker/registry_finder_spec.rb b/npm_and_yarn/spec/dependabot/npm_and_yarn/update_checker/registry_finder_spec.rb
index a631cb3717..e21a63da98 100644
--- a/npm_and_yarn/spec/dependabot/npm_and_yarn/update_checker/registry_finder_spec.rb
+++ b/npm_and_yarn/spec/dependabot/npm_and_yarn/update_checker/registry_finder_spec.rb
@@ -37,6 +37,40 @@
   end
   let(:source) { nil }
 
+  describe "registry_from_rc" do
+    subject { finder.registry_from_rc(dependency_name) }
+
+    let(:dependency_name) { "some_dep" }
+
+    it { is_expected.to eq("https://registry.npmjs.org") }
+
+    context "with a global npm registry" do
+      let(:npmrc_file) { Dependabot::DependencyFile.new(name: ".npmrc", content: "registry=http://example.com") }
+
+      it { is_expected.to eq("http://example.com") }
+    end
+
+    context "with a global yarn registry" do
+      let(:yarnrc_file) { Dependabot::DependencyFile.new(name: ".yarnrc", content: 'registry "http://example.com"') }
+
+      it { is_expected.to eq("http://example.com") }
+    end
+
+    context "with a scoped npm registry" do
+      let(:dependency_name) { "@dependabot/some_dep" }
+      let(:npmrc_file) { Dependabot::DependencyFile.new(name: ".npmrc", content: "@dependabot:registry=http://example.com") }
+
+      it { is_expected.to eq("http://example.com") }
+    end
+
+    context "with a scoped yarn registry" do
+      let(:dependency_name) { "@dependabot/some_dep" }
+      let(:yarnrc_file) { Dependabot::DependencyFile.new(name: ".yarnrc", content: '"@dependabot:registry" "http://example.com"') }
+
+      it { is_expected.to eq("http://example.com") }
+    end
+  end
+
   describe "registry" do
     subject { finder.registry }
 
diff --git a/npm_and_yarn/spec/fixtures/projects/npm8/library_with_global_registry/.npmrc b/npm_and_yarn/spec/fixtures/projects/npm8/library_with_global_registry/.npmrc
new file mode 100644
index 0000000000..a6b36cf454
--- /dev/null
+++ b/npm_and_yarn/spec/fixtures/projects/npm8/library_with_global_registry/.npmrc
@@ -0,0 +1 @@
+registry=http://example.com/dependabot
diff --git a/npm_and_yarn/spec/fixtures/projects/npm8/library_with_global_registry/package.json b/npm_and_yarn/spec/fixtures/projects/npm8/library_with_global_registry/package.json
new file mode 100644
index 0000000000..3b3156d94a
--- /dev/null
+++ b/npm_and_yarn/spec/fixtures/projects/npm8/library_with_global_registry/package.json
@@ -0,0 +1,44 @@
+{
+  "name": "etag",
+  "description": "Create simple ETags",
+  "version": "1.8.0",
+  "contributors": [
+    "Douglas Christopher Wilson <doug@somethingdoug.com>",
+    "David Björklund <david.bjorklund@gmail.com>"
+  ],
+  "license": "MIT",
+  "keywords": [
+    "etag",
+    "http",
+    "res"
+  ],
+  "repository": "jshttp/etag",
+  "devDependencies": {
+    "beautify-benchmark": "0.2.4",
+    "benchmark": "2.1.3",
+    "eslint": "3.15.0",
+    "eslint-config-standard": "6.2.1",
+    "eslint-plugin-markdown": "1.0.0-beta.3",
+    "eslint-plugin-promise": "3.4.2",
+    "eslint-plugin-standard": "2.0.1",
+    "istanbul": "0.4.5",
+    "mocha": "1.21.5",
+    "seedrandom": "2.4.2"
+  },
+  "files": [
+    "LICENSE",
+    "HISTORY.md",
+    "README.md",
+    "index.js"
+  ],
+  "engines": {
+    "node": ">= 0.6"
+  },
+  "scripts": {
+    "bench": "node benchmark/index.js",
+    "lint": "eslint --plugin markdown --ext js,md .",
+    "test": "mocha --reporter spec --bail --check-leaks test/",
+    "test-cov": "istanbul cover node_modules/mocha/bin/_mocha -- --reporter dot --check-leaks test/",
+    "test-travis": "istanbul cover node_modules/mocha/bin/_mocha --report lcovonly -- --reporter spec --check-leaks test/"
+  }
+}
diff --git a/npm_and_yarn/spec/fixtures/projects/npm8/library_with_scoped_registry/.npmrc b/npm_and_yarn/spec/fixtures/projects/npm8/library_with_scoped_registry/.npmrc
new file mode 100644
index 0000000000..182423a082
--- /dev/null
+++ b/npm_and_yarn/spec/fixtures/projects/npm8/library_with_scoped_registry/.npmrc
@@ -0,0 +1 @@
+@dependabot:registry=http://example.com/dependabot
diff --git a/npm_and_yarn/spec/fixtures/projects/npm8/library_with_scoped_registry/package.json b/npm_and_yarn/spec/fixtures/projects/npm8/library_with_scoped_registry/package.json
new file mode 100644
index 0000000000..20e108dc9e
--- /dev/null
+++ b/npm_and_yarn/spec/fixtures/projects/npm8/library_with_scoped_registry/package.json
@@ -0,0 +1,44 @@
+{
+  "name": "@dependabot/etag",
+  "description": "Create simple ETags",
+  "version": "1.8.0",
+  "contributors": [
+    "Douglas Christopher Wilson <doug@somethingdoug.com>",
+    "David Björklund <david.bjorklund@gmail.com>"
+  ],
+  "license": "MIT",
+  "keywords": [
+    "etag",
+    "http",
+    "res"
+  ],
+  "repository": "jshttp/etag",
+  "devDependencies": {
+    "beautify-benchmark": "0.2.4",
+    "benchmark": "2.1.3",
+    "eslint": "3.15.0",
+    "eslint-config-standard": "6.2.1",
+    "eslint-plugin-markdown": "1.0.0-beta.3",
+    "eslint-plugin-promise": "3.4.2",
+    "eslint-plugin-standard": "2.0.1",
+    "istanbul": "0.4.5",
+    "mocha": "1.21.5",
+    "seedrandom": "2.4.2"
+  },
+  "files": [
+    "LICENSE",
+    "HISTORY.md",
+    "README.md",
+    "index.js"
+  ],
+  "engines": {
+    "node": ">= 0.6"
+  },
+  "scripts": {
+    "bench": "node benchmark/index.js",
+    "lint": "eslint --plugin markdown --ext js,md .",
+    "test": "mocha --reporter spec --bail --check-leaks test/",
+    "test-cov": "istanbul cover node_modules/mocha/bin/_mocha -- --reporter dot --check-leaks test/",
+    "test-travis": "istanbul cover node_modules/mocha/bin/_mocha --report lcovonly -- --reporter spec --check-leaks test/"
+  }
+}