diff --git a/csharp/src/Microsoft.ML.OnnxRuntime/Exceptions.cs b/csharp/src/Microsoft.ML.OnnxRuntime/Exceptions.cs
index 47647dba2b..3e677e517d 100644
--- a/csharp/src/Microsoft.ML.OnnxRuntime/Exceptions.cs
+++ b/csharp/src/Microsoft.ML.OnnxRuntime/Exceptions.cs
@@ -32,15 +32,6 @@ namespace Microsoft.ML.OnnxRuntime
     /// The Exception that is thrown for errors related ton OnnxRuntime
     /// </summary>
     public class OnnxRuntimeException: Exception
-    {
-        public OnnxRuntimeException(string message)
-            :base(message)
-        {
-        }
-    }
-
-
-    internal class CoreRuntimeException : OnnxRuntimeException
     {
         private static Dictionary<ErrorCode, string> errorCodeToString = new Dictionary<ErrorCode, string>()
         {
@@ -59,7 +50,7 @@ namespace Microsoft.ML.OnnxRuntime
             { ErrorCode.RequirementNotRegistered, "RequirementNotRegistered" }
         };
 
-        public CoreRuntimeException(ErrorCode errorCode, string message)
+        internal OnnxRuntimeException(ErrorCode errorCode, string message)
             :base("[ErrorCode:" + errorCodeToString[errorCode] + "] " + message)
         {
         }
diff --git a/csharp/src/Microsoft.ML.OnnxRuntime/NativeApiStatus.cs b/csharp/src/Microsoft.ML.OnnxRuntime/NativeApiStatus.cs
index bc4626d549..131a9212a7 100644
--- a/csharp/src/Microsoft.ML.OnnxRuntime/NativeApiStatus.cs
+++ b/csharp/src/Microsoft.ML.OnnxRuntime/NativeApiStatus.cs
@@ -28,7 +28,7 @@ namespace Microsoft.ML.OnnxRuntime
                 ErrorCode statusCode = NativeMethods.ONNXRuntimeGetErrorCode(nativeStatus);
                 string errorMessage = GetErrorMessage(nativeStatus);
                 NativeMethods.ReleaseONNXStatus(nativeStatus);
-                throw new CoreRuntimeException(statusCode, errorMessage);
+                throw new OnnxRuntimeException(statusCode, errorMessage);
             }
         }
     }
diff --git a/csharp/test/Microsoft.ML.OnnxRuntime.Tests/InferenceTest.cs b/csharp/test/Microsoft.ML.OnnxRuntime.Tests/InferenceTest.cs
index ffb1851cb2..b7a747f76f 100644
--- a/csharp/test/Microsoft.ML.OnnxRuntime.Tests/InferenceTest.cs
+++ b/csharp/test/Microsoft.ML.OnnxRuntime.Tests/InferenceTest.cs
@@ -112,7 +112,7 @@ namespace Microsoft.ML.OnnxRuntime.Tests
             var inputMeta = session.InputMetadata;
             var container = new List<NamedOnnxValue>();
             container.Add(NamedOnnxValue.CreateFromTensor<float>("wrong_name", tensor));
-            var ex = Assert.Throws<CoreRuntimeException>(() => session.Run(container));
+            var ex = Assert.Throws<OnnxRuntimeException>(() => session.Run(container));
             Assert.Equal("[ErrorCode:InvalidArgument] Invalid Feed Input Names: wrong_name Valid input names are: data_0 ", ex.Message);
             session.Dispose();
         }
@@ -128,7 +128,7 @@ namespace Microsoft.ML.OnnxRuntime.Tests
             int[] inputDataInt = inputData.Select(x => (int)x).ToArray();
             var tensor = new DenseTensor<int>(inputDataInt, inputMeta["data_0"].Dimensions);
             container.Add(NamedOnnxValue.CreateFromTensor<int>("data_0", tensor));
-            var ex = Assert.Throws<CoreRuntimeException>(() => session.Run(container));
+            var ex = Assert.Throws<OnnxRuntimeException>(() => session.Run(container));
             Assert.Equal("[ErrorCode:InvalidArgument] Unexpected input data type. Actual: (class onnxruntime::NonOnnxType<int>) , expected: (class onnxruntime::NonOnnxType<float>)", ex.Message);
             session.Dispose();
         }
@@ -143,7 +143,7 @@ namespace Microsoft.ML.OnnxRuntime.Tests
             var inputData = new float[] { 0.1f, 0.2f, 0.3f };
             var tensor = new DenseTensor<float>(inputData, new int[] { 1, 3 });
             container.Add(NamedOnnxValue.CreateFromTensor<float>("data_0", tensor));
-            var ex = Assert.Throws<CoreRuntimeException>(() => session.Run(container));
+            var ex = Assert.Throws<OnnxRuntimeException>(() => session.Run(container));
             Assert.Equal("[ErrorCode:Fail] X num_dims does not match W num_dims. X: {1,3} W: {64,3,3,3}", ex.Message);
             session.Dispose();
         }
@@ -160,7 +160,7 @@ namespace Microsoft.ML.OnnxRuntime.Tests
             var nov = NamedOnnxValue.CreateFromTensor<float>("data_0", tensor);
             container.Add(nov);
             container.Add(nov);
-            var ex = Assert.Throws<CoreRuntimeException>(() => session.Run(container));
+            var ex = Assert.Throws<OnnxRuntimeException>(() => session.Run(container));
             Assert.Equal("[ErrorCode:InvalidArgument] duplicated input name", ex.Message);
             session.Dispose();
         }
@@ -178,7 +178,7 @@ namespace Microsoft.ML.OnnxRuntime.Tests
             var nov2 = NamedOnnxValue.CreateFromTensor<float>("extra", tensor);
             container.Add(nov1);
             container.Add(nov2);
-            var ex = Assert.Throws<CoreRuntimeException>(() => session.Run(container));
+            var ex = Assert.Throws<OnnxRuntimeException>(() => session.Run(container));
             Assert.Equal("[ErrorCode:InvalidArgument] The number of feeds is not same as the number of the model input, expect 1 got 2", ex.Message);
             session.Dispose();
         }