diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7f9ea54ec..b824d7152 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Bugfixes
 
 * Update Go runtime to 1.20.4. [#987](https://github.com/elastic/package-registry/pull/987) [#1002](https://github.com/elastic/package-registry/pull/1002)
+* Add fields related to subcategories into categories entrypoint with proxy mode [#1004](https://github.com/elastic/package-registry/pull/1004)
 
 ### Added
 
diff --git a/categories.go b/categories.go
index a5db1e7ab..39e160a1b 100644
--- a/categories.go
+++ b/categories.go
@@ -72,9 +72,11 @@ func categoriesHandlerWithProxyMode(logger *zap.Logger, indexer Indexer, proxyMo
 			for _, category := range proxiedCategories {
 				if _, ok := categories[category.Id]; !ok {
 					categories[category.Id] = &packages.Category{
-						Id:    category.Id,
-						Title: category.Title,
-						Count: category.Count,
+						Id:          category.Id,
+						Title:       category.Title,
+						Count:       category.Count,
+						ParentId:    category.ParentId,
+						ParentTitle: category.ParentTitle,
 					}
 				} else {
 					categories[category.Id].Count += category.Count
diff --git a/proxy_mode_test.go b/proxy_mode_test.go
new file mode 100644
index 000000000..7c03d7dd7
--- /dev/null
+++ b/proxy_mode_test.go
@@ -0,0 +1,71 @@
+// Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+// or more contributor license agreements. Licensed under the Elastic License;
+// you may not use this file except in compliance with the Elastic License.
+
+package main
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/elastic/package-registry/packages"
+	"github.com/elastic/package-registry/proxymode"
+)
+
+func TestCategoriesWithProxyMode(t *testing.T) {
+	webServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		response := `[
+  {
+    "id": "custom",
+    "title": "Custom",
+    "count": 10
+  },
+  {
+    "id": "custom_logs",
+    "title": "Custom Logs",
+    "count": 3,
+    "parent_id": "custom",
+    "parent_title": "Custom"
+  }
+]`
+		w.Header().Set("Content-Type", "application/json")
+		fmt.Fprintln(w, response)
+	}))
+	defer webServer.Close()
+
+	indexerProxy := packages.NewFileSystemIndexer(testLogger, "./testdata/second_package_path")
+	err := indexerProxy.Init(context.Background())
+	require.NoError(t, err)
+
+	proxyMode, err := proxymode.NewProxyMode(
+		testLogger,
+		proxymode.ProxyOptions{
+			Enabled: true,
+			ProxyTo: webServer.URL,
+		},
+	)
+	require.NoError(t, err)
+
+	categoriesWithProxyHandler := categoriesHandlerWithProxyMode(testLogger, indexerProxy, proxyMode, testCacheTime)
+
+	tests := []struct {
+		endpoint string
+		path     string
+		file     string
+		handler  func(w http.ResponseWriter, r *http.Request)
+	}{
+		{"/categories", "/categories", "categories-proxy.json", categoriesWithProxyHandler},
+		{"/categories?kibana.version=6.5.0", "/categories", "categories-proxy-kibana-filter.json", categoriesWithProxyHandler},
+	}
+
+	for _, test := range tests {
+		t.Run(test.endpoint, func(t *testing.T) {
+			runEndpoint(t, test.endpoint, test.path, test.file, test.handler)
+		})
+	}
+}
diff --git a/testdata/generated/categories-proxy-kibana-filter.json b/testdata/generated/categories-proxy-kibana-filter.json
new file mode 100644
index 000000000..913fe004b
--- /dev/null
+++ b/testdata/generated/categories-proxy-kibana-filter.json
@@ -0,0 +1,15 @@
+[
+  {
+    "id": "custom",
+    "title": "Custom",
+    "count": 10
+  },
+  {
+    "id": "custom_logs",
+    "title": "Custom Logs",
+    "count": 3,
+    "parent_id": "custom",
+    "parent_title": "Custom"
+  }
+]
+
diff --git a/testdata/generated/categories-proxy.json b/testdata/generated/categories-proxy.json
new file mode 100644
index 000000000..a0c51f46f
--- /dev/null
+++ b/testdata/generated/categories-proxy.json
@@ -0,0 +1,22 @@
+[
+  {
+    "id": "custom",
+    "title": "Custom",
+    "count": 11
+  },
+  {
+    "id": "custom_logs",
+    "title": "Custom Logs",
+    "count": 3,
+    "parent_id": "custom",
+    "parent_title": "Custom"
+  },
+  {
+    "id": "web",
+    "title": "Web Server",
+    "count": 1,
+    "parent_id": "observability",
+    "parent_title": "Observability"
+  }
+]
+