diff --git a/src/ObjectPool/src/LeakTrackingObjectPool.cs b/src/ObjectPool/src/LeakTrackingObjectPool.cs
index 5fd3f07b1c23..f3b478e781e7 100644
--- a/src/ObjectPool/src/LeakTrackingObjectPool.cs
+++ b/src/ObjectPool/src/LeakTrackingObjectPool.cs
@@ -16,6 +16,8 @@ namespace Microsoft.Extensions.ObjectPool;
 /// </para>
 /// </summary>
 /// <typeparam name="T">The type of object which is being pooled.</typeparam>
+[Obsolete("LeakTrackingObjectPool<T> was only intended for internal use in diagnostic builds of .NET. " +
+    "It never functioned in publicly shipped .NET versions and may be removed in a future release.")]
 public class LeakTrackingObjectPool<T> : ObjectPool<T> where T : class
 {
     private readonly ConditionalWeakTable<T, Tracker> _trackers = new ConditionalWeakTable<T, Tracker>();
diff --git a/src/ObjectPool/src/LeakTrackingObjectPoolProvider.cs b/src/ObjectPool/src/LeakTrackingObjectPoolProvider.cs
index 561ca00e7dbf..9482dbbadc9f 100644
--- a/src/ObjectPool/src/LeakTrackingObjectPoolProvider.cs
+++ b/src/ObjectPool/src/LeakTrackingObjectPoolProvider.cs
@@ -9,6 +9,8 @@ namespace Microsoft.Extensions.ObjectPool;
 /// An <see cref="ObjectPoolProvider"/> that produces instances of
 /// <see cref="LeakTrackingObjectPool{T}"/>.
 /// </summary>
+[Obsolete("LeakTrackingObjectPoolProvider was only intended for internal use in diagnostic builds of .NET. " +
+    "It never functioned in publicly shipped .NET versions and may be removed in a future release.")]
 public class LeakTrackingObjectPoolProvider : ObjectPoolProvider
 {
     private readonly ObjectPoolProvider _inner;