diff --git a/src/NzbDrone.Common.Test/Http/HttpRequestBuilderFixture.cs b/src/NzbDrone.Common.Test/Http/HttpRequestBuilderFixture.cs
index 4af9bb501..74e7e12a0 100644
--- a/src/NzbDrone.Common.Test/Http/HttpRequestBuilderFixture.cs
+++ b/src/NzbDrone.Common.Test/Http/HttpRequestBuilderFixture.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Text;
 using FluentAssertions;
 using NUnit.Framework;
 using NzbDrone.Common.Http;
@@ -9,6 +10,12 @@ namespace NzbDrone.Common.Test.Http
     [TestFixture]
     public class HttpRequestBuilderFixture : TestBase
     {
+        [OneTimeSetUp]
+        public void RegisterEncodingProvider()
+        {
+            Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);
+        }
+
         [TestCase("http://host/{seg}/some", "http://host/dir/some")]
         [TestCase("http://host/some/{seg}", "http://host/some/dir")]
         public void should_add_single_segment_url_segments(string url, string result)
@@ -36,5 +43,70 @@ public void should_remove_duplicated_slashes()
 
             request.Url.FullUri.Should().Be("http://domain/v1/");
         }
+
+        [Test]
+        public void should_encode_form_parameters_with_utf8_by_default()
+        {
+            var builder = new HttpRequestBuilder("http://domain/login")
+                .Post()
+                .AddFormParameter("username", "Привет");
+
+            var request = builder.Build();
+            var body = Encoding.UTF8.GetString(request.ContentData);
+
+            // UTF-8 encoding: Привет = %D0%9F%D1%80%D0%B8%D0%B2%D0%B5%D1%82
+            body.Should().Contain("username=%D0%9F%D1%80%D0%B8%D0%B2%D0%B5%D1%82");
+        }
+
+        [Test]
+        public void should_encode_form_parameters_with_windows_1251_for_cyrillic()
+        {
+            var windows1251 = Encoding.GetEncoding("windows-1251");
+
+            var builder = new HttpRequestBuilder("http://domain/login")
+                .Post()
+                .SetEncoding(windows1251)
+                .AddFormParameter("username", "Привет");
+
+            var request = builder.Build();
+            var body = windows1251.GetString(request.ContentData);
+
+            // Windows-1251 encoding: Привет = %CF%F0%E8%E2%E5%F2
+            body.Should().Contain("username=%CF%F0%E8%E2%E5%F2");
+        }
+
+        [Test]
+        public void should_encode_form_parameters_with_iso_8859_1_for_extended_latin()
+        {
+            var iso88591 = Encoding.GetEncoding("iso-8859-1");
+
+            var builder = new HttpRequestBuilder("http://domain/login")
+                .Post()
+                .SetEncoding(iso88591)
+                .AddFormParameter("username", "café");
+
+            var request = builder.Build();
+            var body = iso88591.GetString(request.ContentData);
+
+            // ISO-8859-1 encoding: é = %E9
+            body.Should().Contain("username=caf%E9");
+        }
+
+        [Test]
+        public void should_encode_form_parameters_ascii_same_regardless_of_encoding()
+        {
+            var windows1251 = Encoding.GetEncoding("windows-1251");
+
+            var builder = new HttpRequestBuilder("http://domain/login")
+                .Post()
+                .SetEncoding(windows1251)
+                .AddFormParameter("username", "testuser")
+                .AddFormParameter("password", "pass123");
+
+            var request = builder.Build();
+            var body = windows1251.GetString(request.ContentData);
+
+            body.Should().Be("username=testuser&password=pass123");
+        }
     }
 }
diff --git a/src/NzbDrone.Common/Http/HttpRequestBuilder.cs b/src/NzbDrone.Common/Http/HttpRequestBuilder.cs
index e5bc3e36b..807ef0032 100644
--- a/src/NzbDrone.Common/Http/HttpRequestBuilder.cs
+++ b/src/NzbDrone.Common/Http/HttpRequestBuilder.cs
@@ -231,7 +231,7 @@ protected virtual void ApplyFormData(HttpRequest request)
             }
             else
             {
-                var parameters = FormData.Select(v => string.Format("{0}={1}", v.Name, Uri.EscapeDataString(Encoding.GetString(v.ContentData))));
+                var parameters = FormData.Select(v => string.Format("{0}={1}", v.Name, Encoding.GetString(v.ContentData).UrlEncode(Encoding)));
                 var urlencoded = string.Join("&", parameters);
                 var body = Encoding.GetBytes(urlencoded);
 
diff --git a/src/NzbDrone.Core/Indexers/Definitions/FunFile.cs b/src/NzbDrone.Core/Indexers/Definitions/FunFile.cs
index 927dcc21c..91646cb37 100644
--- a/src/NzbDrone.Core/Indexers/Definitions/FunFile.cs
+++ b/src/NzbDrone.Core/Indexers/Definitions/FunFile.cs
@@ -58,6 +58,7 @@ protected override async Task DoLogin()
         };
 
         var authLoginRequest = requestBuilder
+            .SetEncoding(Encoding)
             .AddFormParameter("username", Settings.Username)
             .AddFormParameter("password", Settings.Password)
             .AddFormParameter("returnto", "")
diff --git a/src/NzbDrone.Core/Indexers/Definitions/PornoLab.cs b/src/NzbDrone.Core/Indexers/Definitions/PornoLab.cs
index 8952375ff..ab9723ee7 100644
--- a/src/NzbDrone.Core/Indexers/Definitions/PornoLab.cs
+++ b/src/NzbDrone.Core/Indexers/Definitions/PornoLab.cs
@@ -57,6 +57,7 @@ protected override async Task DoLogin()
             };
 
             var authLoginRequest = requestBuilder
+                .SetEncoding(Encoding)
                 .AddFormParameter("login_username", Settings.Username)
                 .AddFormParameter("login_password", Settings.Password)
                 .AddFormParameter("login", "Login")
diff --git a/src/NzbDrone.Core/Indexers/Definitions/PreToMe.cs b/src/NzbDrone.Core/Indexers/Definitions/PreToMe.cs
index 10c8276e7..043e5000a 100644
--- a/src/NzbDrone.Core/Indexers/Definitions/PreToMe.cs
+++ b/src/NzbDrone.Core/Indexers/Definitions/PreToMe.cs
@@ -66,6 +66,7 @@ protected override async Task DoLogin()
         };
 
         var authLoginRequest = requestBuilder
+            .SetEncoding(Encoding)
             .SetCookies(loginPage.GetCookies())
             .AddFormParameter("username", Settings.Username)
             .AddFormParameter("password", Settings.Password)
diff --git a/src/NzbDrone.Core/Indexers/Definitions/RuTracker.cs b/src/NzbDrone.Core/Indexers/Definitions/RuTracker.cs
index dc1ebfa14..86ad314c7 100644
--- a/src/NzbDrone.Core/Indexers/Definitions/RuTracker.cs
+++ b/src/NzbDrone.Core/Indexers/Definitions/RuTracker.cs
@@ -91,6 +91,7 @@ protected override async Task DoLogin()
             Cookies = null;
 
             var authLoginRequest = requestBuilder.Post()
+                .SetEncoding(Encoding)
                 .AddFormParameter("login_username", Settings.Username)
                 .AddFormParameter("login_password", Settings.Password)
                 .AddFormParameter("login", "Login")
diff --git a/src/NzbDrone.Core/Indexers/Definitions/TorrentBytes.cs b/src/NzbDrone.Core/Indexers/Definitions/TorrentBytes.cs
index efda3329b..08b04ff48 100644
--- a/src/NzbDrone.Core/Indexers/Definitions/TorrentBytes.cs
+++ b/src/NzbDrone.Core/Indexers/Definitions/TorrentBytes.cs
@@ -58,6 +58,7 @@ protected override async Task DoLogin()
             Cookies = null;
 
             var authLoginRequest = requestBuilder
+                .SetEncoding(Encoding)
                 .AddFormParameter("username", Settings.Username)
                 .AddFormParameter("password", Settings.Password)
                 .AddFormParameter("returnto", "/")