diff --git a/Source/CFRunLoop.c b/Source/CFRunLoop.c
index 2c5322da..88a4ad23 100644
--- a/Source/CFRunLoop.c
+++ b/Source/CFRunLoop.c
@@ -1521,7 +1521,7 @@ CFRunLoopSourceRemoveInvalidated(const void *key, const void *value, void *sourc
 {
   GSRunLoopContextRef ctxt = (GSRunLoopContextRef) value;
   CFIndex idx = CFArrayGetFirstIndexOfValue(ctxt->sources0,
-                                            CFRangeMake(0, CFArrayGetCount(ctxt->timers)),
+                                            CFRangeMake(0, CFArrayGetCount(ctxt->sources0)),
                                             (CFRunLoopSourceRef) source);
   
   if (idx != -1)
diff --git a/Tests/CFRunLoop/source_invalidate.m b/Tests/CFRunLoop/source_invalidate.m
new file mode 100644
index 00000000..bef10cdb
--- /dev/null
+++ b/Tests/CFRunLoop/source_invalidate.m
@@ -0,0 +1,30 @@
+#include "CoreFoundation/CFRunLoop.h"
+#include "../CFTesting.h"
+#include <string.h>
+
+static void perform (void *info)
+{
+}
+
+int main (void)
+{
+  CFRunLoopRef rl;
+  CFRunLoopSourceContext ctx;
+  CFRunLoopSourceRef src;
+
+  rl = CFRunLoopGetCurrent ();
+  memset (&ctx, 0, sizeof (ctx));
+  ctx.perform = perform;
+  src = CFRunLoopSourceCreate (NULL, 0, &ctx);
+  CFRunLoopAddSource (rl, src, kCFRunLoopDefaultMode);
+  PASS_CF(CFRunLoopContainsSource (rl, src, kCFRunLoopDefaultMode) == true,
+    "Source is in the run loop after being added.");
+
+  /* No timers are registered. */
+  CFRunLoopSourceInvalidate (src);
+  PASS_CF(CFRunLoopContainsSource (rl, src, kCFRunLoopDefaultMode) == false,
+    "Invalidated source is removed from the run loop.");
+
+  CFRelease (src);
+  return 0;
+}