diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4ad4d1362..bc6127cbe 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,11 +3,11 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 
 ## [Unreleased]
 ### Added
-- Added base64 gem to gemspec (#218)[https://github.com/opensearch-project/opensearch-ruby/pull/218]
 - Added support for Ruby 3.3 ([#220](https://github.com/opensearch-project/opensearch-ruby/pull/220))
 ### Changed
 ### Deprecated
 ### Removed
+- Removed dependency on the base64 gem ([#221](https://github.com/opensearch-project/opensearch-ruby/pull/221))
 ### Fixed
 - Switch back to the latest OpenSearch version when testing in CI ([#219](https://github.com/opensearch-project/opensearch-ruby/pull/219))
 ### Security
diff --git a/lib/opensearch/transport/client.rb b/lib/opensearch/transport/client.rb
index acbb92814..ee4b60af2 100644
--- a/lib/opensearch/transport/client.rb
+++ b/lib/opensearch/transport/client.rb
@@ -24,8 +24,6 @@
 # specific language governing permissions and limitations
 # under the License.
 
-require 'base64'
-
 module OpenSearch
   module Transport
     # Handles communication with an OpenSearch cluster.
@@ -225,7 +223,8 @@ def extract_cloud_creds(arguments)
         return unless arguments[:cloud_id] && !arguments[:cloud_id].empty?
 
         name = arguments[:cloud_id].split(':')[0]
-        cloud_url, opensearch_instance = Base64.decode64(arguments[:cloud_id].gsub("#{name}:", '')).split('$')
+        base64_decoded = arguments[:cloud_id].gsub("#{name}:", '').unpack1('m')
+        cloud_url, opensearch_instance = base64_decoded.split('$')
 
         if cloud_url.include?(':')
           url, port = cloud_url.split(':')
@@ -355,7 +354,8 @@ def __auto_detect_adapter
       # Encode credentials for the Authorization Header
       # Credentials is the base64 encoding of id and api_key joined by a colon
       def __encode(api_key)
-        Base64.strict_encode64([api_key[:id], api_key[:api_key]].join(':'))
+        joined = [api_key[:id], api_key[:api_key]].join(':')
+        [joined].pack('m0')
       end
     end
   end
diff --git a/opensearch-ruby.gemspec b/opensearch-ruby.gemspec
index ab1f9a1c1..f86f69800 100644
--- a/opensearch-ruby.gemspec
+++ b/opensearch-ruby.gemspec
@@ -64,7 +64,6 @@ Gem::Specification.new do |s|
 
   s.required_ruby_version = '>= 2.5'
 
-  s.add_dependency 'base64'
   s.add_dependency 'faraday', '>= 1.0', '< 3'
   s.add_dependency 'multi_json', '>= 1.0'
 end
diff --git a/spec/opensearch/transport/client_spec.rb b/spec/opensearch/transport/client_spec.rb
index 8d556cfb1..050dc458f 100644
--- a/spec/opensearch/transport/client_spec.rb
+++ b/spec/opensearch/transport/client_spec.rb
@@ -98,7 +98,8 @@
     end
 
     it 'Adds the ApiKey header to the connection' do
-      expect(authorization_header).to eq("ApiKey #{Base64.strict_encode64('my_id:my_api_key')}")
+      strict_base64_encoded = ["my_id:my_api_key"].pack("m0")
+      expect(authorization_header).to eq("ApiKey #{strict_base64_encoded}")
     end
   end