diff --git a/cmd/gateway-s3.go b/cmd/gateway-s3.go
index 454fcae98..d36c9bcef 100644
--- a/cmd/gateway-s3.go
+++ b/cmd/gateway-s3.go
@@ -85,6 +85,10 @@ func s3ToObjectError(err error, params ...string) error {
 		}
 	case "XAmzContentSHA256Mismatch":
 		err = SHA256Mismatch{}
+	case "NoSuchUpload":
+		err = InvalidUploadID{}
+	case "EntityTooSmall":
+		err = PartTooSmall{}
 	}
 
 	e.e = err
@@ -195,7 +199,7 @@ func (l *s3Objects) GetBucketInfo(bucket string) (bi BucketInfo, e error) {
 func (l *s3Objects) ListBuckets() ([]BucketInfo, error) {
 	buckets, err := l.Client.ListBuckets()
 	if err != nil {
-		return nil, err
+		return nil, s3ToObjectError(traceError(err))
 	}
 
 	b := make([]BucketInfo, len(buckets))
@@ -450,7 +454,11 @@ func toMinioClientMetadata(metadata map[string]string) map[string]string {
 func (l *s3Objects) NewMultipartUpload(bucket string, object string, metadata map[string]string) (uploadID string, err error) {
 	// Create PutObject options
 	opts := minio.PutObjectOptions{UserMetadata: metadata}
-	return l.Client.NewMultipartUpload(bucket, object, opts)
+	uploadID, err = l.Client.NewMultipartUpload(bucket, object, opts)
+	if err != nil {
+		return uploadID, s3ToObjectError(traceError(err), bucket, object)
+	}
+	return uploadID, nil
 }
 
 // CopyObjectPart copy part of object to other bucket and object
@@ -473,7 +481,7 @@ func fromMinioClientObjectPart(op minio.ObjectPart) PartInfo {
 func (l *s3Objects) PutObjectPart(bucket string, object string, uploadID string, partID int, data *HashReader) (pi PartInfo, e error) {
 	md5HexBytes, err := hex.DecodeString(data.md5Sum)
 	if err != nil {
-		return pi, err
+		return pi, s3ToObjectError(traceError(err), bucket, object)
 	}
 
 	sha256sumBytes, err := hex.DecodeString(data.sha256Sum)
@@ -483,7 +491,7 @@ func (l *s3Objects) PutObjectPart(bucket string, object string, uploadID string,
 
 	info, err := l.Client.PutObjectPart(bucket, object, uploadID, partID, data, data.Size(), md5HexBytes, sha256sumBytes)
 	if err != nil {
-		return pi, err
+		return pi, s3ToObjectError(traceError(err), bucket, object)
 	}
 
 	return fromMinioClientObjectPart(info), nil
@@ -526,7 +534,8 @@ func (l *s3Objects) ListObjectParts(bucket string, object string, uploadID strin
 
 // AbortMultipartUpload aborts a ongoing multipart upload
 func (l *s3Objects) AbortMultipartUpload(bucket string, object string, uploadID string) error {
-	return l.Client.AbortMultipartUpload(bucket, object, uploadID)
+	err := l.Client.AbortMultipartUpload(bucket, object, uploadID)
+	return s3ToObjectError(traceError(err), bucket, object)
 }
 
 // toMinioClientCompletePart converts completePart to minio CompletePart
diff --git a/cmd/gateway-s3_test.go b/cmd/gateway-s3_test.go
new file mode 100644
index 000000000..cf0fe01be
--- /dev/null
+++ b/cmd/gateway-s3_test.go
@@ -0,0 +1,120 @@
+/*
+ * Minio Cloud Storage, (C) 2017 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package cmd
+
+import (
+	"errors"
+	"testing"
+
+	minio "github.com/minio/minio-go"
+)
+
+func errResponse(code string) minio.ErrorResponse {
+	return minio.ErrorResponse{
+		Code: code,
+	}
+}
+
+func TestS3ToObjectError(t *testing.T) {
+	testCases := []struct {
+		inputErr       error
+		expectedErr    error
+		bucket, object string
+	}{
+		{
+			inputErr:    errResponse("BucketAlreadyOwnedByYou"),
+			expectedErr: BucketAlreadyOwnedByYou{},
+		},
+		{
+			inputErr:    errResponse("BucketNotEmpty"),
+			expectedErr: BucketNotEmpty{},
+		},
+		{
+			inputErr:    errResponse("InvalidBucketName"),
+			expectedErr: BucketNameInvalid{},
+		},
+		{
+			inputErr:    errResponse("NoSuchBucketPolicy"),
+			expectedErr: PolicyNotFound{},
+		},
+		{
+			inputErr:    errResponse("NoSuchBucket"),
+			expectedErr: BucketNotFound{},
+		},
+		// with empty Object in minio.ErrorRepsonse, NoSuchKey
+		// is interpreted as BucketNotFound
+		{
+			inputErr:    errResponse("NoSuchKey"),
+			expectedErr: BucketNotFound{},
+		},
+		{
+			inputErr:    errResponse("NoSuchUpload"),
+			expectedErr: InvalidUploadID{},
+		},
+		{
+			inputErr:    errResponse("XMinioInvalidObjectName"),
+			expectedErr: ObjectNameInvalid{},
+		},
+		{
+			inputErr:    errResponse("AccessDenied"),
+			expectedErr: PrefixAccessDenied{},
+		},
+		{
+			inputErr:    errResponse("XAmzContentSHA256Mismatch"),
+			expectedErr: SHA256Mismatch{},
+		},
+		{
+			inputErr:    errResponse("EntityTooSmall"),
+			expectedErr: PartTooSmall{},
+		},
+		{
+			inputErr:    nil,
+			expectedErr: nil,
+		},
+		// Special test case for NoSuchKey with object name
+		{
+			inputErr: minio.ErrorResponse{
+				Code: "NoSuchKey",
+			},
+			expectedErr: ObjectNotFound{},
+			bucket:      "bucket",
+			object:      "obbject",
+		},
+
+		// N B error values that aren't of expected types
+		// should be left untouched.
+		// Special test case for error that is not of type
+		// minio.ErrorResponse
+		{
+			inputErr:    errors.New("not a minio.ErrorResponse"),
+			expectedErr: errors.New("not a minio.ErrorResponse"),
+		},
+		// Special test case for error value that is not of
+		// type (*Error)
+		{
+			inputErr:    errors.New("not a *Error"),
+			expectedErr: errors.New("not a *Error"),
+		},
+	}
+
+	for i, tc := range testCases {
+		actualErr := s3ToObjectError(tc.inputErr, tc.bucket, tc.object)
+		if e, ok := actualErr.(*Error); ok && e.e != tc.expectedErr {
+			t.Errorf("Test case %d: Expected error %v but received error %v", i+1, tc.expectedErr, e.e)
+		}
+	}
+}