diff --git a/src/NzbDrone.Common.Test/Http/HttpUriFixture.cs b/src/NzbDrone.Common.Test/Http/HttpUriFixture.cs
new file mode 100644
index 000000000..099ab990f
--- /dev/null
+++ b/src/NzbDrone.Common.Test/Http/HttpUriFixture.cs
@@ -0,0 +1,84 @@
+using FluentAssertions;
+using NUnit.Framework;
+using NzbDrone.Common.Http;
+using NzbDrone.Test.Common;
+
+namespace NzbDrone.Common.Test.Http
+{
+    public class HttpUriFixture : TestBase
+    {
+        [TestCase("", "", "")]
+        [TestCase("/", "", "/")]
+        [TestCase("base", "", "base")]
+        [TestCase("/base", "", "/base")]
+        [TestCase("/base/", "", "/base/")]
+        [TestCase("", "relative", "relative")]
+        [TestCase("", "/relative", "/relative")]
+        [TestCase("/", "relative", "/relative")]
+        [TestCase("/", "/relative", "/relative")]
+        [TestCase("base", "relative", "relative")]
+        [TestCase("base", "/relative", "/relative")]
+        [TestCase("/base", "relative", "/relative")]
+        [TestCase("/base", "/relative", "/relative")]
+        [TestCase("/base/", "relative", "/base/relative")]
+        [TestCase("/base/", "/relative", "/relative")]
+        [TestCase("base/sub", "relative", "base/relative")]
+        [TestCase("base/sub", "/relative", "/relative")]
+        [TestCase("/base/sub", "relative", "/base/relative")]
+        [TestCase("/base/sub", "/relative", "/relative")]
+        [TestCase("/base/sub/", "relative", "/base/sub/relative")]
+        [TestCase("/base/sub/", "/relative", "/relative")]
+        [TestCase("abc://host.com:8080/root/file.xml", "relative/path", "abc://host.com:8080/root/relative/path")]
+        [TestCase("abc://host.com:8080/root/file.xml", "/relative/path", "abc://host.com:8080/relative/path")]
+        [TestCase("abc://host.com:8080/root/file.xml?query=1#fragment", "relative/path", "abc://host.com:8080/root/relative/path")]
+        [TestCase("abc://host.com:8080/root/file.xml?query=1#fragment", "/relative/path", "abc://host.com:8080/relative/path")]
+        [TestCase("abc://host.com:8080/root/api", "relative/path", "abc://host.com:8080/root/relative/path")]
+        [TestCase("abc://host.com:8080/root/api", "/relative/path", "abc://host.com:8080/relative/path")]
+        [TestCase("abc://host.com:8080/root/api/", "relative/path", "abc://host.com:8080/root/api/relative/path")]
+        [TestCase("abc://host.com:8080/root/api/", "/relative/path", "abc://host.com:8080/relative/path")]
+        [TestCase("abc://host.com:8080/root/api/", "//otherhost.com/path", "abc://otherhost.com/path")]
+        public void should_combine_uri(string basePath, string relativePath, string expected)
+        {
+            var newUri = new HttpUri(basePath) + new HttpUri(relativePath);
+            newUri.FullUri.Should().Be(expected);
+        }
+
+        [TestCase("", "", "")]
+        [TestCase("/", "", "/")]
+        [TestCase("base", "", "base")]
+        [TestCase("/base", "", "/base")]
+        [TestCase("/base/", "", "/base/")]
+        [TestCase("", "relative", "relative")]
+        [TestCase("", "/relative", "/relative")]
+        [TestCase("/", "relative", "/relative")]
+        [TestCase("/", "/relative", "/relative")]
+        [TestCase("base", "relative", "base/relative")]
+        [TestCase("base", "/relative", "base/relative")]
+        [TestCase("/base", "relative", "/base/relative")]
+        [TestCase("/base", "/relative", "/base/relative")]
+        [TestCase("/base/", "relative", "/base/relative")]
+        [TestCase("/base/", "/relative", "/base/relative")]
+        [TestCase("base/sub", "relative", "base/sub/relative")]
+        [TestCase("base/sub", "/relative", "base/sub/relative")]
+        [TestCase("/base/sub", "relative", "/base/sub/relative")]
+        [TestCase("/base/sub", "/relative", "/base/sub/relative")]
+        [TestCase("/base/sub/", "relative", "/base/sub/relative")]
+        [TestCase("/base/sub/", "/relative", "/base/sub/relative")]
+        [TestCase("/base/sub/", "relative/", "/base/sub/relative/")]
+        [TestCase("/base/sub/", "/relative/", "/base/sub/relative/")]
+        [TestCase("abc://host.com:8080/root/file.xml", "relative/path", "abc://host.com:8080/root/file.xml/relative/path")]
+        [TestCase("abc://host.com:8080/root/file.xml", "/relative/path", "abc://host.com:8080/root/file.xml/relative/path")]
+        [TestCase("abc://host.com:8080/root/file.xml?query=1#fragment", "relative/path", "abc://host.com:8080/root/file.xml/relative/path?query=1#fragment")]
+        [TestCase("abc://host.com:8080/root/file.xml?query=1#fragment", "/relative/path", "abc://host.com:8080/root/file.xml/relative/path?query=1#fragment")]
+        [TestCase("abc://host.com:8080/root/api", "relative/path", "abc://host.com:8080/root/api/relative/path")]
+        [TestCase("abc://host.com:8080/root/api", "/relative/path", "abc://host.com:8080/root/api/relative/path")]
+        [TestCase("abc://host.com:8080/root/api/", "relative/path", "abc://host.com:8080/root/api/relative/path")]
+        [TestCase("abc://host.com:8080/root/api/", "/relative/path", "abc://host.com:8080/root/api/relative/path")]
+        public void should_combine_relative_path(string basePath, string relativePath, string expected)
+        {
+            var newUri = new HttpUri(basePath).CombinePath(relativePath);
+            
+            newUri.FullUri.Should().Be(expected);
+        }
+    }
+}
diff --git a/src/NzbDrone.Common.Test/NzbDrone.Common.Test.csproj b/src/NzbDrone.Common.Test/NzbDrone.Common.Test.csproj
index 338a9e926..84892c6b1 100644
--- a/src/NzbDrone.Common.Test/NzbDrone.Common.Test.csproj
+++ b/src/NzbDrone.Common.Test/NzbDrone.Common.Test.csproj
@@ -83,6 +83,7 @@
     <Compile Include="Http\HttpClientFixture.cs" />
     <Compile Include="Http\HttpRequestBuilderFixture.cs" />
     <Compile Include="Http\HttpRequestFixture.cs" />
+    <Compile Include="Http\HttpUriFixture.cs" />
     <Compile Include="InstrumentationTests\CleanseLogMessageFixture.cs" />
     <Compile Include="LevenshteinDistanceFixture.cs" />
     <Compile Include="OsPathFixture.cs" />
diff --git a/src/NzbDrone.Common/Http/HttpUri.cs b/src/NzbDrone.Common/Http/HttpUri.cs
index c8c83de66..a52a06137 100644
--- a/src/NzbDrone.Common/Http/HttpUri.cs
+++ b/src/NzbDrone.Common/Http/HttpUri.cs
@@ -131,7 +131,7 @@ namespace NzbDrone.Common.Http
                 return _queryParams;
             }
         }
-        
+
         public HttpUri CombinePath(string path)
         {
             return new HttpUri(Scheme, Host, Port, CombinePath(Path, path), Query, Fragment);
@@ -144,23 +144,34 @@ namespace NzbDrone.Common.Http
                 return basePath;
             }
 
-            var newPath = "/" + relativePath.TrimStart('/');
-
-            if (basePath != null && !relativePath.StartsWith("/"))
+            if (basePath.IsNullOrWhiteSpace())
             {
-                var baseSlashIndex = basePath.LastIndexOf('/');
-
-                if (baseSlashIndex == basePath.Length - 1)
-                {
-                    newPath = basePath.TrimEnd('/') + newPath;
-                }
-                else if (baseSlashIndex != 0)
-                {
-                    newPath = basePath.Substring(0, baseSlashIndex) + newPath;
-                }
+                return relativePath;
             }
 
-            return newPath;
+            return basePath.TrimEnd('/') + "/" + relativePath.TrimStart('/');
+        }
+
+        private static string CombineRelativePath(string basePath, string relativePath)
+        {
+            if (relativePath.IsNullOrWhiteSpace())
+            {
+                return basePath;
+            }
+
+            if (relativePath.StartsWith("/"))
+            {
+                return relativePath;
+            }
+
+            var baseSlashIndex = basePath.LastIndexOf('/');
+
+            if (baseSlashIndex >= 0)
+            {
+                return basePath.Substring(0, baseSlashIndex) + "/" + relativePath;
+            }
+            
+            return relativePath;
         }
 
         public HttpUri SetQuery(string query)
@@ -252,7 +263,7 @@ namespace NzbDrone.Common.Http
 
             if (relativeUrl.Path.IsNotNullOrWhiteSpace())
             {
-                return new HttpUri(baseUrl.Scheme, baseUrl.Host, baseUrl.Port, HttpUri.CombinePath(baseUrl.Path, relativeUrl.Path), relativeUrl.Query, relativeUrl.Fragment);
+                return new HttpUri(baseUrl.Scheme, baseUrl.Host, baseUrl.Port, CombineRelativePath(baseUrl.Path, relativeUrl.Path), relativeUrl.Query, relativeUrl.Fragment);
             }
             
             return new HttpUri(baseUrl.Scheme, baseUrl.Host, baseUrl.Port, baseUrl.Path, relativeUrl.Query, relativeUrl.Fragment);