diff --git a/LoveSeat.IntegrationTest/CouchClientTest.cs b/LoveSeat.IntegrationTest/CouchClientTest.cs
index b83d29a..228aa30 100644
--- a/LoveSeat.IntegrationTest/CouchClientTest.cs
+++ b/LoveSeat.IntegrationTest/CouchClientTest.cs
@@ -128,6 +128,25 @@ public void Should_Return_Attachment_Names()
 			Assert.IsTrue(doc.GetAttachmentNames().Contains("martin.jpg"));
 		}
 
+		[Test]
+		public void Should_UrlEncode_Attachment_Names()
+		{
+			// Attachment filenames should be URL-encoded to allow them to be round-tripped.
+			// e.g. given a filename of "url%20encoded.jpg", note that it is already url-encoded ('%20' is the encoded form of ' ').
+			// Thus, in order to preserve the filename, it must be url-encoded an additional time.
+			
+			var db = client.GetDatabase(baseDatabase);
+			db.CreateDocument(@"{""_id"":""upload""}");
+			var attachment = File.ReadAllBytes("../../Files/martin.jpg");
+			db.AddAttachment("upload", attachment, "url%20encoded.jpg", "image/jpeg");
+			db.AddAttachment("upload", attachment, "not url encoded.jpg", "image/jpeg");
+			var doc = db.GetDocument("upload");
+			var attachments = doc.GetAttachmentNames().ToList();
+			foreach (var filename in attachments) { System.Diagnostics.Trace.WriteLine(filename); }
+			Assert.IsTrue(attachments.Contains("url%20encoded.jpg"), "Attachments with filenames that are already url-encoded should be encoded to round-trip their name accurately.");
+			Assert.IsTrue(attachments.Contains("not url encoded.jpg"), "Attachments with non-url-encoded filenames should be persisted accurately.");
+		}
+
 		[Test]
 		public void Should_Create_Admin_User()
 		{			
diff --git a/LoveSeat/CouchDatabase.cs b/LoveSeat/CouchDatabase.cs
index b40d698..d1f2907 100644
--- a/LoveSeat/CouchDatabase.cs
+++ b/LoveSeat/CouchDatabase.cs
@@ -213,7 +213,7 @@ public CouchResponseObject AddAttachment(string id, byte[] attachment, string fi
         public CouchResponseObject AddAttachment(string id, string rev, byte[] attachment, string filename, string contentType)
         {
             return
-                GetRequest(string.Format("{0}/{1}/{2}?rev={3}", databaseBaseUri, id, filename, rev)).Put().ContentType(contentType).Data(attachment).GetCouchResponse().GetJObject();
+                GetRequest(string.Format("{0}/{1}/{2}?rev={3}", databaseBaseUri, id, HttpUtility.UrlEncode(filename), rev)).Put().ContentType(contentType).Data(attachment).GetCouchResponse().GetJObject();
         }
         /// <summary>
         /// Adds an attachment to a document.  If revision is not specified then the most recent will be fetched and used.  Warning: if you need document update conflicts to occur please use the method that specifies the revision
@@ -238,7 +238,7 @@ public CouchResponseObject AddAttachment(string id, Stream attachmentStream, str
         public CouchResponseObject AddAttachment(string id, string rev, Stream attachmentStream, string filename, string contentType)
         {
             return
-                GetRequest(string.Format("{0}/{1}/{2}?rev={3}", databaseBaseUri, id, filename, rev)).Put().ContentType(contentType).Data(attachmentStream).GetCouchResponse().GetJObject();
+                GetRequest(string.Format("{0}/{1}/{2}?rev={3}", databaseBaseUri, id, HttpUtility.UrlEncode(filename), rev)).Put().ContentType(contentType).Data(attachmentStream).GetCouchResponse().GetJObject();
         }
 
         public Stream GetAttachmentStream(Document doc, string attachmentName)