diff --git a/srfi/srfi-1.scm b/srfi/srfi-1.scm
index 5529d6201..e355431bd 100644
--- a/srfi/srfi-1.scm
+++ b/srfi/srfi-1.scm
@@ -730,20 +730,22 @@
 
 (define (filter-map f clist1 . rest)
   (if (null? rest)
-    (let lp ((l clist1))
+    (let lp ((l clist1)
+	     (rl '()))
       (if (null? l)
-	'()
+	(reverse! rl)
 	(let ((res (f (car l))))
 	  (if res
-	    (cons res (lp (cdr l)))
-	    (lp (cdr l))))))
-    (let lp ((l (cons clist1 rest)))
+	    (lp (cdr l) (cons res rl))
+	    (lp (cdr l) rl)))))
+    (let lp ((l (cons clist1 rest))
+	     (rl '()))
       (if (any1 null? l)
-	'()
+	(reverse! rl)
 	(let ((res (apply f (map1 car l))))
 	  (if res
-	    (cons res (lp (map1 cdr l)))
-	    (lp (map1 cdr l))))))))
+	    (lp (map1 cdr l) (cons res rl))
+	    (lp (map1 cdr l) rl)))))))
 
 ;;; Filtering & partitioning