diff --git a/src/csharp/Grpc.Core.Tests/ClientBaseTest.cs b/src/csharp/Grpc.Core.Tests/ClientBaseTest.cs
new file mode 100644
index 0000000000000000000000000000000000000000..2dc10ebe971a2c536bda5dc903b93e23f2b9c389
--- /dev/null
+++ b/src/csharp/Grpc.Core.Tests/ClientBaseTest.cs
@@ -0,0 +1,62 @@
+#region Copyright notice and license
+
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#endregion
+
+using System;
+using Grpc.Core;
+using Grpc.Core.Internal;
+using Grpc.Core.Utils;
+using NUnit.Framework;
+
+namespace Grpc.Core.Tests
+{
+    public class ClientBaseTest
+    {
+        [Test]
+        public void GetAuthUriBase_Valid()
+        {
+            Assert.AreEqual("https://some.googleapi.com/", ClientBase.GetAuthUriBase("some.googleapi.com"));
+            Assert.AreEqual("https://some.googleapi.com/", ClientBase.GetAuthUriBase("dns:///some.googleapi.com/"));
+            Assert.AreEqual("https://some.googleapi.com/", ClientBase.GetAuthUriBase("dns:///some.googleapi.com:443/"));
+            Assert.AreEqual("https://some.googleapi.com/", ClientBase.GetAuthUriBase("some.googleapi.com:443/"));
+        }
+
+        [Test]
+        public void GetAuthUriBase_Invalid()
+        {
+            Assert.IsNull(ClientBase.GetAuthUriBase("some.googleapi.com:"));
+            Assert.IsNull(ClientBase.GetAuthUriBase("https://some.googleapi.com/"));
+            Assert.IsNull(ClientBase.GetAuthUriBase("dns://some.googleapi.com:443"));  // just two slashes
+            Assert.IsNull(ClientBase.GetAuthUriBase(""));
+        }
+    }
+}
diff --git a/src/csharp/Grpc.Core.Tests/Grpc.Core.Tests.csproj b/src/csharp/Grpc.Core.Tests/Grpc.Core.Tests.csproj
index 97ee0454bb0938a3bdadf25ff2e715a16e2c089f..d6a8f52570b1d3ee2103f4842d0cd7c797bdc98b 100644
--- a/src/csharp/Grpc.Core.Tests/Grpc.Core.Tests.csproj
+++ b/src/csharp/Grpc.Core.Tests/Grpc.Core.Tests.csproj
@@ -63,6 +63,7 @@
     <Compile Include="..\Grpc.Core\Version.cs">
       <Link>Version.cs</Link>
     </Compile>
+    <Compile Include="ClientBaseTest.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="ClientServerTest.cs" />
     <Compile Include="ServerTest.cs" />
diff --git a/src/csharp/Grpc.Core/ClientBase.cs b/src/csharp/Grpc.Core/ClientBase.cs
index f46184406c5da96a504e176684c7dcf51d48716e..f240d777b9c4a014cbc82d2a3b6fa77b0913342a 100644
--- a/src/csharp/Grpc.Core/ClientBase.cs
+++ b/src/csharp/Grpc.Core/ClientBase.cs
@@ -33,9 +33,10 @@
 
 using System;
 using System.Collections.Generic;
+using System.Text.RegularExpressions;
 
 using Grpc.Core.Internal;
-using System.Text.RegularExpressions;
+using Grpc.Core.Utils;
 
 namespace Grpc.Core
 {
@@ -46,15 +47,16 @@ namespace Grpc.Core
     /// </summary>
     public abstract class ClientBase
     {
-        static readonly Regex TrailingPortPattern = new Regex(":[0-9]+/?$");
+        // Regex for removal of the optional DNS scheme, trailing port, and trailing backslash
+        static readonly Regex ChannelTargetPattern = new Regex(@"^(dns:\/{3})?([^:\/]+)(:\d+)?\/?$");
+
         readonly Channel channel;
         readonly string authUriBase;
 
         public ClientBase(Channel channel)
         {
             this.channel = channel;
-            // TODO(jtattermush): we shouldn't need to hand-curate the channel.Target contents.
-            this.authUriBase = "https://" + TrailingPortPattern.Replace(channel.Target, "") + "/";
+            this.authUriBase = GetAuthUriBase(channel.Target);
         }
 
         /// <summary>
@@ -104,10 +106,23 @@ namespace Grpc.Core
                 {
                     options = options.WithHeaders(new Metadata());
                 }
-                var authUri = authUriBase + method.ServiceName;
+                var authUri = authUriBase != null ? authUriBase + method.ServiceName : null;
                 interceptor(authUri, options.Headers);
             }
             return new CallInvocationDetails<TRequest, TResponse>(channel, method, Host, options);
         }
+
+        /// <summary>
+        /// Creates Auth URI base from channel's target (the one passed at channel creation).
+        /// Fully-qualified service name is to be appended to this.
+        /// </summary>
+        internal static string GetAuthUriBase(string target)
+        {
+            var match = ChannelTargetPattern.Match(target);
+            if (!match.Success) {
+                return null;
+            }
+            return "https://" + match.Groups[2].Value + "/";
+        }
     }
 }