diff --git a/mcs/class/corlib/System.Runtime.Remoting/RemotingServices.cs b/mcs/class/corlib/System.Runtime.Remoting/RemotingServices.cs
index 815c1ba7e737..422302eaf071 100644
--- a/mcs/class/corlib/System.Runtime.Remoting/RemotingServices.cs
+++ b/mcs/class/corlib/System.Runtime.Remoting/RemotingServices.cs
@@ -780,7 +780,9 @@ internal static byte[] SerializeCallData (object obj)
 			
 			if (obj == null) return null;
 			MemoryStream ms = new MemoryStream ();
-			_serializationFormatter.Serialize (ms, obj);
+			lock (_serializationFormatter) {
+				_serializationFormatter.Serialize (ms, obj);
+			}
 			return ms.ToArray ();
 		}
 
@@ -791,7 +793,10 @@ internal static object DeserializeCallData (byte[] array)
 			if (array == null) return null;
 			
 			MemoryStream ms = new MemoryStream (array);
-			object obj = _deserializationFormatter.Deserialize (ms);
+			object obj;
+			lock (_deserializationFormatter) {
+				obj = _deserializationFormatter.Deserialize (ms);
+			}
 			
 			if (obj is CACD) {
 				CACD cad = (CACD) obj;
@@ -813,7 +818,9 @@ internal static byte[] SerializeExceptionData (Exception ex)
 				/* empty - we're only interested in the protected block */
 			} finally {
 				MemoryStream ms = new MemoryStream ();
-				_serializationFormatter.Serialize (ms, ex);
+				lock (_serializationFormatter) {
+					_serializationFormatter.Serialize (ms, ex);
+				}
 				result = ms.ToArray ();
 			}
 			return result;
diff --git a/mcs/class/corlib/Test/System.Runtime.Remoting/RemotingServicesTest.cs b/mcs/class/corlib/Test/System.Runtime.Remoting/RemotingServicesTest.cs
new file mode 100644
index 000000000000..9391a27a7693
--- /dev/null
+++ b/mcs/class/corlib/Test/System.Runtime.Remoting/RemotingServicesTest.cs
@@ -0,0 +1,60 @@
+//
+// MonoTests.System.Runtime.Remoting.RemotingServicesTest.cs
+//
+// Author: Alexis Christoforides (alchri@microsoft.com)
+//
+// 2018 (C) Copyright, Novell, Inc.
+//
+
+using System;
+using System.Reflection;
+using System.Threading.Tasks;
+using NUnit.Framework;
+
+namespace MonoTests.System.Runtime.Remoting
+{
+	[TestFixture]
+	public class RemotingServicesTest
+	{
+		public class AppDomainObject : MarshalByRefObject
+		{
+			public void Init(CrossDomainSerializedObject applicationDependencies) // racy exception here
+			{
+
+			}
+		}
+
+		public class CrossDomainSerializedObject : MarshalByRefObject
+		{
+		}
+		private static CrossDomainSerializedObject crossDomainSerializedObject;
+
+		private static void AppDomainWithRemotingSerialization(Assembly assembly, string name)
+		{
+				var appDomain = AppDomain.CreateDomain(name);
+				var appDomainObject = (AppDomainObject)appDomain.CreateInstanceAndUnwrap(assembly.GetName().Name, typeof(AppDomainObject).FullName);
+				appDomainObject.Init(crossDomainSerializedObject);
+		}
+
+		[Test]
+		public void Bug46473 () // concurrent serialization/deserialization
+		{
+			bool success = true;
+			crossDomainSerializedObject = new CrossDomainSerializedObject();
+			Task[] tasks = new Task [20];
+			for (int i = 0; i < tasks.Length; i++)
+			{
+				var assembly = Assembly.GetAssembly(typeof(AppDomainObject));
+				var name = "AppDomainWithCall" + i;
+				tasks [i] = Task.Factory.StartNew(() => AppDomainWithRemotingSerialization(assembly, name));
+			}
+			try {
+				Task.WaitAll (tasks);
+			} catch (AggregateException e) {
+				success = false;
+				Console.WriteLine ($"{e}, {e.InnerException}");
+			}
+			Assert.IsTrue (success, "Bug46473 (exception during remoting call)");
+		}
+	}
+}
diff --git a/mcs/class/corlib/corlib_test.dll.sources b/mcs/class/corlib/corlib_test.dll.sources
index 507c39c4a7f4..25f8303e576f 100644
--- a/mcs/class/corlib/corlib_test.dll.sources
+++ b/mcs/class/corlib/corlib_test.dll.sources
@@ -220,6 +220,7 @@ System.Runtime.InteropServices/StructLayoutAttributeTest.cs
 System.Runtime.Remoting/ContextTest.cs
 System.Runtime.Remoting/SoapServicesTest.cs
 System.Runtime.Remoting/SynchronizationAttributeTest.cs
+System.Runtime.Remoting/RemotingServicesTest.cs
 System.Runtime.Remoting.Channels/ChannelServicesTest.cs
 System.Runtime.Remoting.Contexts/SynchronizationAttributeTest.cs
 System.Runtime.Remoting.Messaging/CallContextTest.cs
diff --git a/mcs/class/corlib/monotouch_corlib_test.dll.exclude.sources b/mcs/class/corlib/monotouch_corlib_test.dll.exclude.sources
index 10192e46f4b0..4148534997b5 100644
--- a/mcs/class/corlib/monotouch_corlib_test.dll.exclude.sources
+++ b/mcs/class/corlib/monotouch_corlib_test.dll.exclude.sources
@@ -41,6 +41,7 @@ System.Runtime.Remoting/ContextTest.cs
 System.Runtime.Remoting/RemotingConfigurationTest.cs
 System.Runtime.Remoting/SoapServicesTest.cs
 System.Runtime.Remoting/SynchronizationAttributeTest.cs
+System.Runtime.Remoting/RemotingServicesTest.cs
 System.Security.AccessControl/AuthorizationRuleTest.cs
 System.Security.AccessControl/CommonAceTest.cs
 System.Security.AccessControl/CommonAclTest.cs
diff --git a/mcs/class/corlib/testing_aot_full_corlib_test.dll.exclude.sources b/mcs/class/corlib/testing_aot_full_corlib_test.dll.exclude.sources
index 8b08b22c32e0..13f84f69e1d6 100644
--- a/mcs/class/corlib/testing_aot_full_corlib_test.dll.exclude.sources
+++ b/mcs/class/corlib/testing_aot_full_corlib_test.dll.exclude.sources
@@ -35,6 +35,7 @@ System.Runtime.Remoting/ContextTest.cs
 System.Runtime.Remoting/RemotingConfigurationTest.cs
 System.Runtime.Remoting/SoapServicesTest.cs
 System.Runtime.Remoting/SynchronizationAttributeTest.cs
+System.Runtime.Remoting/RemotingServicesTest.cs
 System.Runtime.Remoting.Channels/ChannelServicesTest.cs
 System.Runtime.Remoting.Contexts/SynchronizationAttributeTest.cs
 System.Runtime.Remoting.Messaging/CallContextTest.cs
diff --git a/mcs/class/corlib/wasm_corlib_test.dll.exclude.sources b/mcs/class/corlib/wasm_corlib_test.dll.exclude.sources
index 8b08b22c32e0..13f84f69e1d6 100644
--- a/mcs/class/corlib/wasm_corlib_test.dll.exclude.sources
+++ b/mcs/class/corlib/wasm_corlib_test.dll.exclude.sources
@@ -35,6 +35,7 @@ System.Runtime.Remoting/ContextTest.cs
 System.Runtime.Remoting/RemotingConfigurationTest.cs
 System.Runtime.Remoting/SoapServicesTest.cs
 System.Runtime.Remoting/SynchronizationAttributeTest.cs
+System.Runtime.Remoting/RemotingServicesTest.cs
 System.Runtime.Remoting.Channels/ChannelServicesTest.cs
 System.Runtime.Remoting.Contexts/SynchronizationAttributeTest.cs
 System.Runtime.Remoting.Messaging/CallContextTest.cs