diff --git a/lib/isc/pthreads/include/isc/thread.h b/lib/isc/pthreads/include/isc/thread.h
index e0e05456ed..6c5143dd83 100644
--- a/lib/isc/pthreads/include/isc/thread.h
+++ b/lib/isc/pthreads/include/isc/thread.h
@@ -17,10 +17,6 @@ typedef isc_threadresult_t (*isc_threadfunc_t)(isc_threadarg_t);
 	((pthread_create((tp), NULL, (s), (a)) == 0) ? \
 	 ISC_R_SUCCESS : ISC_R_UNEXPECTED)
 
-#define isc_thread_detach(t) \
-	((pthread_detach((t)) == 0) ? \
-	 ISC_R_SUCCESS : ISC_R_UNEXPECTED)
-
 #define isc_thread_join(t, rp) \
 	((pthread_join((t), (rp)) == 0) ? \
 	 ISC_R_SUCCESS : ISC_R_UNEXPECTED)
diff --git a/lib/isc/win32/include/isc/thread.h b/lib/isc/win32/include/isc/thread.h
index 9bc35659fc..1b8e780d35 100644
--- a/lib/isc/win32/include/isc/thread.h
+++ b/lib/isc/win32/include/isc/thread.h
@@ -14,7 +14,6 @@ typedef isc_threadresult_t (WINAPI *isc_threadfunc_t)(isc_threadarg_t);
 isc_result_t isc_thread_create(isc_threadfunc_t, isc_threadarg_t, 
 			       isc_thread_t *);
 isc_result_t isc_thread_join(isc_thread_t, isc_threadresult_t *);
-isc_result_t isc_thread_detach(isc_thread_t);
 #define isc_thread_self \
 	(unsigned long)GetCurrentThreadId
 
diff --git a/lib/isc/win32/thread.c b/lib/isc/win32/thread.c
index be0515ebf6..bb0a2dfa3d 100644
--- a/lib/isc/win32/thread.c
+++ b/lib/isc/win32/thread.c
@@ -36,10 +36,3 @@ isc_thread_join(isc_thread_t thread, isc_threadresult_t *rp) {
 
 	return (ISC_R_SUCCESS);
 }
-
-isc_result_t isc_thread_detach(isc_thread_t thread) {
-
-	/* XXX */
-
-	return (ISC_R_SUCCESS);
-}