diff --git a/README.md b/README.md
index 8a5cab6c..7438f85e 100644
--- a/README.md
+++ b/README.md
@@ -13,9 +13,12 @@ The WireMock admin API provides functionality to define the mappings via a http
 ### /__admin/mappings
 The mappings defined in the mock service.
 * `GET    /__admin/mappings` --> Gets all defined mappings
-* `DELETE /__admin/mappings` --> Create a new stub mapping
-* `POST   /__admin/mappings` --> TODO
+* `POST   /__admin/mappings` --> Create a new stub mapping
 * `DELETE /__admin/mappings` --> TODO
+* `GET    /__admin/mappings/{guid}` --> Get a single stub mapping
+* `PUT    /__admin/mappings/{guid}` --> TODO
+* `POST   /__admin/mappings/{guid}` --> TODO
+* `DELETE /__admin/mappings/{guid}` --> TODO
 
 ### /__admin/requests
 Logged requests and responses received by the mock service.
diff --git a/src/WireMock.Net/Server/FluentMockServer.Admin.cs b/src/WireMock.Net/Server/FluentMockServer.Admin.cs
index 233f0c99..6bf03e73 100644
--- a/src/WireMock.Net/Server/FluentMockServer.Admin.cs
+++ b/src/WireMock.Net/Server/FluentMockServer.Admin.cs
@@ -17,6 +17,9 @@ namespace WireMock.Server
     /// </summary>
     public partial class FluentMockServer
     {
+        private const string AdminMappings = "/__admin/mappings";
+        private const string AdminRequests = "/__admin/requests";
+
         private readonly JsonSerializerSettings _settings = new JsonSerializerSettings
         {
             Formatting = Formatting.None,
@@ -25,10 +28,27 @@ namespace WireMock.Server
 
         private void InitAdmin()
         {
-            Given(Request.Create().WithUrl("/__admin/mappings").UsingGet()).RespondWith(new DynamicResponseProvider(MappingsGet));
-            Given(Request.Create().WithUrl("/__admin/mappings").UsingPost()).RespondWith(new DynamicResponseProvider(MappingsPost));
+            // __admin/mappings
+            Given(Request.Create().WithUrl(AdminMappings).UsingGet()).RespondWith(new DynamicResponseProvider(MappingsGet));
+            Given(Request.Create().WithUrl(AdminMappings).UsingPost()).RespondWith(new DynamicResponseProvider(MappingsPost));
 
-            Given(Request.Create().WithUrl("/__admin/requests").UsingGet()).RespondWith(new DynamicResponseProvider(RequestsGet));
+            // __admin/mappings/{guid}
+            var guidPathMatcher = new RegexMatcher(@"^\/__admin\/mappings\/(\{{0,1}([0-9a-fA-F]){8}-([0-9a-fA-F]){4}-([0-9a-fA-F]){4}-([0-9a-fA-F]){4}-([0-9a-fA-F]){12}\}{0,1})$");
+            Given(Request.Create().WithPath(guidPathMatcher).UsingGet()).RespondWith(new DynamicResponseProvider(MappingGet));
+
+
+            // __admin/requests
+            Given(Request.Create().WithUrl(AdminRequests).UsingGet()).RespondWith(new DynamicResponseProvider(RequestsGet));
+        }
+
+        private ResponseMessage MappingGet(RequestMessage requestMessage)
+        {
+            Guid guid = Guid.Parse(requestMessage.Path.TrimStart(AdminMappings.ToCharArray()));
+            var mapping = Mappings.FirstOrDefault(m => !(m.Provider is DynamicResponseProvider) && m.Guid == guid);
+
+            var model = ToMappingModel(mapping);
+
+            return ToJson(model);
         }
 
         private ResponseMessage MappingsGet(RequestMessage requestMessage)
@@ -248,7 +268,7 @@ namespace WireMock.Server
 
             switch (matcher.Name)
             {
-                case "RegExMatcher":
+                case "RegexMatcher":
                     return new RegexMatcher(matcher.Pattern);
 
                 case "JsonPathMatcher":
diff --git a/src/WireMock.Net/Server/FluentMockServer.cs b/src/WireMock.Net/Server/FluentMockServer.cs
index 2fd4dcbf..6b58605c 100644
--- a/src/WireMock.Net/Server/FluentMockServer.cs
+++ b/src/WireMock.Net/Server/FluentMockServer.cs
@@ -183,6 +183,13 @@ namespace WireMock.Server
         {
             lock (((ICollection)_mappings).SyncRoot)
             {
+                // Check a mapping exists with the same GUI, if so, remove it first.
+                var existingMapping = _mappings.FirstOrDefault(m => m.Guid == mapping.Guid);
+                if (existingMapping != null)
+                {
+                    _mappings.Remove(existingMapping);
+                }
+
                 _mappings.Add(mapping);
             }
         }
@@ -216,8 +223,8 @@ namespace WireMock.Server
 
             try
             {
-                var targetRoute = _mappings.FirstOrDefault(route => route.IsRequestHandled(request));
-                if (targetRoute == null)
+                var targetMapping = _mappings.FirstOrDefault(route => route.IsRequestHandled(request));
+                if (targetMapping == null)
                 {
                     response = new ResponseMessage
                     {
@@ -227,7 +234,7 @@ namespace WireMock.Server
                 }
                 else
                 {
-                    response = await targetRoute.ResponseTo(request);
+                    response = await targetMapping.ResponseTo(request);
                 }
             }
             catch (Exception ex)
diff --git a/test/WireMock.Net.Tests/FluentMockServerTests.cs b/test/WireMock.Net.Tests/FluentMockServerTests.cs
index db80df85..dcf4c433 100644
--- a/test/WireMock.Net.Tests/FluentMockServerTests.cs
+++ b/test/WireMock.Net.Tests/FluentMockServerTests.cs
@@ -20,7 +20,7 @@ namespace WireMock.Net.Tests
         private FluentMockServer _server;
 
         [Test]
-        public void FluentMockServer_get_routes()
+        public void FluentMockServer_Admin_Mappings_Get()
         {
             var guid = Guid.Parse("90356dba-b36c-469a-a17e-669cd84f1f05");
             _server = FluentMockServer.Start();
@@ -32,16 +32,52 @@ namespace WireMock.Net.Tests
             _server.Given(Request.Create().WithUrl("/foo2").UsingGet())
                 .RespondWith(Response.Create().WithStatusCode(202).WithBody("2"));
 
-            var routes = _server.Mappings;
+            var mappings = _server.Mappings.ToArray();
+            Check.That(mappings).HasSize(2);
 
-            var enumerable = routes.ToArray();
-            Check.That(enumerable).HasSize(2);
+            Check.That(mappings.First().RequestMatcher).IsNotNull();
+            Check.That(mappings.First().Provider).IsNotNull();
+            Check.That(mappings.First().Guid).Equals(guid);
 
-            Check.That(enumerable.First().RequestMatcher).IsNotNull();
-            Check.That(enumerable.First().Provider).IsNotNull();
-            Check.That(enumerable.First().Guid).Equals(guid);
+            Check.That(mappings[1].Guid).Not.Equals(guid);
+        }
 
-            Check.That(enumerable[1].Guid).Not.Equals(guid);
+        [Test]
+        public void FluentMockServer_Admin_Mappings_Add_SameGuid()
+        {
+            var guid = Guid.Parse("90356dba-b36c-469a-a17e-669cd84f1f05");
+            _server = FluentMockServer.Start();
+
+            _server.Given(Request.Create().WithUrl("/1").UsingGet())
+                .WithGuid(guid)
+                .RespondWith(Response.Create().WithStatusCode(500));
+
+            var mappings = _server.Mappings.ToArray();
+            Check.That(mappings).HasSize(1);
+            Check.That(mappings.First().Guid).Equals(guid);
+
+            _server.Given(Request.Create().WithUrl("/2").UsingGet())
+                .WithGuid(guid)
+                .RespondWith(Response.Create().WithStatusCode(500));
+
+            Check.That(mappings).HasSize(1);
+            Check.That(mappings.First().Guid).Equals(guid);
+        }
+
+        [Test]
+        public async Task FluentMockServer_Admin_Requests_Get()
+        {
+            // given
+            _server = FluentMockServer.Start();
+
+            // when
+            await new HttpClient().GetAsync("http://localhost:" + _server.Port + "/foo");
+
+            // then
+            Check.That(_server.LogEntries).HasSize(1);
+            var requestLogged = _server.LogEntries.First();
+            Check.That(requestLogged.RequestMessage.Method).IsEqualTo("get");
+            Check.That(requestLogged.RequestMessage.BodyAsBytes).IsNull();
         }
 
         [Test]
@@ -94,22 +130,6 @@ namespace WireMock.Net.Tests
             Check.That((int)response.StatusCode).IsEqualTo(404);
         }
 
-        [Test]
-        public async Task Should_record_requests_in_the_requestlogs()
-        {
-            // given
-            _server = FluentMockServer.Start();
-
-            // when
-            await new HttpClient().GetAsync("http://localhost:" + _server.Port + "/foo");
-
-            // then
-            Check.That(_server.LogEntries).HasSize(1);
-            var requestLogged = _server.LogEntries.First();
-            Check.That(requestLogged.RequestMessage.Method).IsEqualTo("get");
-            Check.That(requestLogged.RequestMessage.BodyAsBytes).IsNull();
-        }
-
         [Test]
         public async Task Should_find_a_request_satisfying_a_request_spec()
         {