diff --git a/TODO b/TODO
index 9ba2329f..03b98412 100644
--- a/TODO
+++ b/TODO
@@ -1,7 +1,6 @@
 Initiatives:
 
 - srfi 18 - missing thread functions, more complex threading examples
-- test on a 64-bit platform/vm
 - api documentation
 - syntax-rules integration (WIP, works sometimes but needs to compile smaller)
 - r7rs missing features
diff --git a/srfi/18.sld b/srfi/18.sld
index b2b6aa76..e5ff42e9 100644
--- a/srfi/18.sld
+++ b/srfi/18.sld
@@ -18,7 +18,7 @@
     thread-start!
     thread-sleep!
     thread-yield!
-    ;; TODO: thread-terminate!
+    thread-terminate!
     ;; TODO: thread-join!
 
     mutex?
@@ -84,7 +84,9 @@
              (mutator-id (Cyc-spawn-thread! thunk)))
         (vector-set! t 2 mutator-id)))
     (define (thread-yield!) (thread-sleep! 1))
-;    (define (thread-terminate!) (Cyc-end-thread!))
+    (define-c thread-terminate!
+      "(void *data, int argc, closure _, object k)"
+      " Cyc_end_thread(data); ")
     ;; TODO: thread-join!
 
     (define-c thread-sleep!