diff --git a/src/WireMock.Net.StandAlone/WireMock.Net.StandAlone.csproj b/src/WireMock.Net.StandAlone/WireMock.Net.StandAlone.csproj
index 622970d0..0791252d 100644
--- a/src/WireMock.Net.StandAlone/WireMock.Net.StandAlone.csproj
+++ b/src/WireMock.Net.StandAlone/WireMock.Net.StandAlone.csproj
@@ -3,7 +3,7 @@
   <PropertyGroup>
     <Description>Lightweight StandAlone Http Mocking Server for .Net.</Description>
     <AssemblyTitle>WireMock.Net.StandAlone</AssemblyTitle>
-    <Version>1.0.2.10</Version>
+    <Version>1.0.2.11</Version>
     <Authors>Stef Heyenrath</Authors>
     <TargetFrameworks>net452;net46;netstandard1.3;netstandard2.0</TargetFrameworks>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
diff --git a/src/WireMock.Net/Server/FluentMockServer.cs b/src/WireMock.Net/Server/FluentMockServer.cs
index 534ac7c8..7eaa7c3a 100644
--- a/src/WireMock.Net/Server/FluentMockServer.cs
+++ b/src/WireMock.Net/Server/FluentMockServer.cs
@@ -363,18 +363,18 @@ namespace WireMock.Server
             return new RespondWithAProvider(RegisterMapping, requestMatcher);
         }
 
-        /// <summary>
-        /// The register mapping.
-        /// </summary>
-        /// <param name="mapping">
-        /// The mapping.
-        /// </param>
         private void RegisterMapping(Mapping mapping)
         {
-            // Check a mapping exists with the same GUID, if so, remove it first.
-            DeleteMapping(mapping.Guid);
-
-            _options.Mappings.Add(mapping);
+            // Check a mapping exists with the same Guid, if so, replace it.
+            var existingMapping = _options.Mappings.FirstOrDefault(m => m.Guid == mapping.Guid);
+            if (existingMapping != null)
+            {
+                _options.Mappings[_options.Mappings.IndexOf(existingMapping)] = mapping;
+            }
+            else
+            {
+                _options.Mappings.Add(mapping);
+            }
         }
     }
 }
\ No newline at end of file
diff --git a/src/WireMock.Net/WireMock.Net.csproj b/src/WireMock.Net/WireMock.Net.csproj
index 8ce020b0..9be9752f 100644
--- a/src/WireMock.Net/WireMock.Net.csproj
+++ b/src/WireMock.Net/WireMock.Net.csproj
@@ -3,7 +3,7 @@
   <PropertyGroup>
     <Description>Lightweight Http Mocking Server for .Net, inspired by WireMock from the Java landscape.</Description>
     <AssemblyTitle>WireMock.Net</AssemblyTitle>
-    <Version>1.0.2.10</Version>
+    <Version>1.0.2.11</Version>
     <Authors>Alexandre Victoor;Stef Heyenrath</Authors>
     <TargetFrameworks>net452;net46;netstandard1.3;netstandard2.0</TargetFrameworks>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
diff --git a/test/WireMock.Net.Tests/FluentMockServerTests.cs b/test/WireMock.Net.Tests/FluentMockServerTests.cs
index deb1f6c7..db45d7af 100644
--- a/test/WireMock.Net.Tests/FluentMockServerTests.cs
+++ b/test/WireMock.Net.Tests/FluentMockServerTests.cs
@@ -117,20 +117,24 @@ namespace WireMock.Net.Tests
             var guid = Guid.Parse("90356dba-b36c-469a-a17e-669cd84f1f05");
             _server = FluentMockServer.Start();
 
-            _server.Given(Request.Create().WithPath("/1").UsingGet())
+            var response1 = Response.Create().WithStatusCode(500);
+            _server.Given(Request.Create().UsingGet())
                 .WithGuid(guid)
-                .RespondWith(Response.Create().WithStatusCode(500));
+                .RespondWith(response1);
 
-            var mappings = _server.Mappings.ToArray();
-            Check.That(mappings).HasSize(1);
-            Check.That(mappings.First().Guid).Equals(guid);
+            var mappings1 = _server.Mappings.ToArray();
+            Check.That(mappings1).HasSize(1);
+            Check.That(mappings1.First().Guid).Equals(guid);
 
+            var response2 = Response.Create().WithStatusCode(400);
             _server.Given(Request.Create().WithPath("/2").UsingGet())
                 .WithGuid(guid)
-                .RespondWith(Response.Create().WithStatusCode(500));
+                .RespondWith(response2);
 
-            Check.That(mappings).HasSize(1);
-            Check.That(mappings.First().Guid).Equals(guid);
+            var mappings2 = _server.Mappings.ToArray();
+            Check.That(mappings2).HasSize(1);
+            Check.That(mappings2.First().Guid).Equals(guid);
+            Check.That(mappings2.First().Provider).Equals(response2);
         }
 
         [Fact]