diff --git a/src/com/android/exchange/adapter/EmailSyncAdapter.java b/src/com/android/exchange/adapter/EmailSyncAdapter.java
index 9b3224848..6f607e170 100644
--- a/src/com/android/exchange/adapter/EmailSyncAdapter.java
+++ b/src/com/android/exchange/adapter/EmailSyncAdapter.java
@@ -295,7 +295,7 @@ public class EmailSyncAdapter extends AbstractSyncAdapter {
             int lastDot = fileName.lastIndexOf('.');
             String extension = null;
             if ((lastDot > 0) && (lastDot < fileName.length() - 1)) {
-                extension = fileName.substring(lastDot + 1);
+                extension = fileName.substring(lastDot + 1).toLowerCase();
             }
             if (extension == null) {
                 // A reasonable default for now.
diff --git a/tests/src/com/android/exchange/EasEmailSyncAdapterTests.java b/tests/src/com/android/exchange/EasEmailSyncAdapterTests.java
index e6f7353d0..a3e7daeec 100644
--- a/tests/src/com/android/exchange/EasEmailSyncAdapterTests.java
+++ b/tests/src/com/android/exchange/EasEmailSyncAdapterTests.java
@@ -69,6 +69,9 @@ public class EasEmailSyncAdapterTests extends AndroidTestCase {
         // Test a few known types
         String mimeType = p.getMimeTypeFromFileName("foo.jpg");
         assertEquals("image/jpeg", mimeType);
+        // Make sure this is case insensitive
+        mimeType = p.getMimeTypeFromFileName("foo.JPG");
+        assertEquals("image/jpeg", mimeType);
         mimeType = p.getMimeTypeFromFileName("this_is_a_weird_filename.gif");
         assertEquals("image/gif", mimeType);
         // Test an illegal file name ending with the extension prefix