diff --git a/generator/.DevConfigs/32a12d7c-afc6-4bcf-a2d8-9c49b335b935.json b/generator/.DevConfigs/32a12d7c-afc6-4bcf-a2d8-9c49b335b935.json
new file mode 100644
index 000000000000..65fb80e5465d
--- /dev/null
+++ b/generator/.DevConfigs/32a12d7c-afc6-4bcf-a2d8-9c49b335b935.json
@@ -0,0 +1,11 @@
+{
+  "services": [
+    {
+      "serviceName": "S3",
+      "type": "patch",
+      "changeLogMessages": [
+        "Fixed issue calling UploadPart with an unseekable stream and disabling checksum failing."
+      ]
+    }
+  ]
+}
\ No newline at end of file
diff --git a/sdk/src/Services/S3/Custom/Internal/AmazonS3PostMarshallHandler.cs b/sdk/src/Services/S3/Custom/Internal/AmazonS3PostMarshallHandler.cs
index 5e2198b0e55b..bedc79a6f595 100644
--- a/sdk/src/Services/S3/Custom/Internal/AmazonS3PostMarshallHandler.cs
+++ b/sdk/src/Services/S3/Custom/Internal/AmazonS3PostMarshallHandler.cs
@@ -125,11 +125,11 @@ private static void SetStreamChecksum(UploadPartRequest uploadPartRequest, IRequ
             if (uploadPartRequest.InputStream != null)
             {
                 // Wrap input stream in partial wrapper (to upload only part of the stream)
-                var partialStream = new PartialWrapperStream(uploadPartRequest.InputStream, uploadPartRequest.PartSize.GetValueOrDefault());
+                var partialStream = GetStreamWithLength(uploadPartRequest.InputStream, uploadPartRequest.PartSize.GetValueOrDefault(), chooseMin: true);
                 if (partialStream.Length > 0 && !(uploadPartRequest.DisablePayloadSigning ?? false))
                     request.UseChunkEncoding = uploadPartRequest.UseChunkEncoding;
                 if (!request.Headers.ContainsKey(HeaderKeys.ContentLengthHeader))
-                    request.Headers.Add(HeaderKeys.ContentLengthHeader, partialStream.Length.ToString(CultureInfo.InvariantCulture));
+                    request.Headers.Add(HeaderKeys.ContentLengthHeader, (partialStream.Length - partialStream.Position).ToString(CultureInfo.InvariantCulture));
 
                 request.DisablePayloadSigning = uploadPartRequest.DisablePayloadSigning;
                 uploadPartRequest.InputStream = partialStream;
@@ -159,7 +159,7 @@ private static void SetStreamChecksum(PutObjectRequest putObjectRequest, IReques
             if (putObjectRequest.InputStream != null)
             {
                 // Wrap the stream in a stream that has a length
-                var streamWithLength = GetStreamWithLength(putObjectRequest.InputStream, putObjectRequest.Headers.ContentLength);
+                var streamWithLength = GetStreamWithLength(putObjectRequest.InputStream, putObjectRequest.Headers.ContentLength, chooseMin: false);
                 if (streamWithLength.Length > 0 && !(putObjectRequest.DisablePayloadSigning ?? false))
                     request.UseChunkEncoding = putObjectRequest.UseChunkEncoding;
                 var length = streamWithLength.Length - streamWithLength.Position;
@@ -190,7 +190,7 @@ private static void SetStreamChecksum(PutObjectRequest putObjectRequest, IReques
         /// If the stream supports seeking, returns stream.
         /// Otherwise, uses hintLength to create a read-only, non-seekable stream of given length
         /// </summary>
-        private static Stream GetStreamWithLength(Stream baseStream, long hintLength)
+        private static Stream GetStreamWithLength(Stream baseStream, long hintLength, bool chooseMin)
         {
             Stream result = baseStream;
             bool shouldWrapStream = false;
@@ -198,6 +198,14 @@ private static Stream GetStreamWithLength(Stream baseStream, long hintLength)
             try
             {
                 length = baseStream.Length - baseStream.Position;
+
+                // If chooseMin is true that means we are uploading a part of a stream and the hintLength
+                // must be treated as the maximum length to read from the baseStream.
+                if (chooseMin && length > hintLength)
+                {
+                    shouldWrapStream = true;
+                    length = hintLength;
+                }
             }
             catch (NotSupportedException)
             {
diff --git a/sdk/test/Services/S3/IntegrationTests/PutUnseekableStreamTests.cs b/sdk/test/Services/S3/IntegrationTests/PutUnseekableStreamTests.cs
new file mode 100644
index 000000000000..76fbeae332c8
--- /dev/null
+++ b/sdk/test/Services/S3/IntegrationTests/PutUnseekableStreamTests.cs
@@ -0,0 +1,130 @@
+using System.IO;
+using System.Text;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+using Amazon.S3;
+using Amazon.S3.Model;
+using Amazon.S3.Util;
+using System.Threading.Tasks;
+
+namespace AWSSDK_DotNet.IntegrationTests.Tests.S3
+{
+    [TestClass]
+    public class PutUnseekableStreamTests : TestBase<AmazonS3Client>
+    {
+        private static string bucketName;
+
+        [ClassInitialize()]
+        public static void Initialize(TestContext a)
+        {
+            StreamWriter writer = File.CreateText("PutObjectFile.txt");
+            writer.Write("This is some sample text.!!");
+            writer.Close();
+
+            bucketName = S3TestUtils.CreateBucketWithWait(Client, true);
+        }
+
+        [ClassCleanup]
+        public static void ClassCleanup()
+        {
+            AmazonS3Util.DeleteS3BucketWithObjects(Client, bucketName);
+            BaseClean();
+        }
+
+        [TestMethod]
+        [TestCategory("S3")]
+        public async Task TestPutObject()
+        {
+            var stream = new CustomStream(Encoding.UTF8.GetBytes("Hello, S3!"));
+            var putRequest = new PutObjectRequest
+            {
+                BucketName = bucketName,
+                Key = "put-object-unseekable-test.txt",
+                InputStream = stream,
+                DisablePayloadSigning = true
+            };
+
+            await Client.PutObjectAsync(putRequest);
+
+            var getRequest = new GetObjectRequest
+            {
+                BucketName = bucketName,
+                Key = "put-object-unseekable-test.txt"
+            };
+            using (var getResponse = await Client.GetObjectAsync(getRequest))
+            {
+                using (var reader = new StreamReader(getResponse.ResponseStream))
+                {
+                    var content = reader.ReadToEnd();
+                    Assert.AreEqual("Hello, S3!", content);
+                }
+            }
+        }
+
+        [TestMethod]
+        [TestCategory("S3")]
+        public async Task TestUploadPart()
+        {
+            var stream = new CustomStream(Encoding.UTF8.GetBytes("Hello, S3!"));
+
+            var initiateMultipartUploadRequest = new InitiateMultipartUploadRequest
+            {
+                BucketName = bucketName,
+                Key = "upload-part-unseekable-test.txt"
+            };
+
+            var initiateMultipartUploadResponse = await Client.InitiateMultipartUploadAsync(initiateMultipartUploadRequest);
+
+            var uploadPartRequest = new UploadPartRequest
+            {
+                BucketName = bucketName,
+                Key = "upload-part-unseekable-test.txt",
+                UploadId = initiateMultipartUploadResponse.UploadId,
+                PartNumber = 1,
+                PartSize = stream.Length,
+                InputStream = stream,
+                DisablePayloadSigning = true,
+                IsLastPart = true,
+            };
+
+
+            var uploadPartResponse = await Client.UploadPartAsync(uploadPartRequest);
+
+            var completeMultipartUploadRequest = new CompleteMultipartUploadRequest
+            {
+                BucketName = bucketName,
+                Key = "upload-part-unseekable-test.txt",
+                UploadId = initiateMultipartUploadResponse.UploadId
+            };
+
+            completeMultipartUploadRequest.AddPartETags(uploadPartResponse);
+
+            await Client.CompleteMultipartUploadAsync(completeMultipartUploadRequest);
+
+            var getRequest = new GetObjectRequest
+            {
+                BucketName = bucketName,
+                Key = "upload-part-unseekable-test.txt"
+            };
+            using (var getResponse = await Client.GetObjectAsync(getRequest))
+            {
+                using (var reader = new StreamReader(getResponse.ResponseStream))
+                {
+                    var content = reader.ReadToEnd();
+                    Assert.AreEqual("Hello, S3!", content);
+                }
+            }
+        }
+
+
+        public class CustomStream : MemoryStream
+        {
+            public CustomStream(byte[] buffer) : base(buffer)
+            {
+            }
+
+            public override bool CanSeek => false;
+
+        }
+    }
+}