diff --git a/scm.mes b/scm.mes
index 0c14d501..eb7f1c82 100755
--- a/scm.mes
+++ b/scm.mes
@@ -182,6 +182,9 @@
 
 (define quotient /)
 
+(define (remainder x y)
+  (- x (* (/ x y) y)))
+
 (define (max x . rest)
   (if (null? rest) x
       (let* ((y (car rest))
diff --git a/test.mes b/test.mes
index ac2f601f..771c5724 100644
--- a/test.mes
+++ b/test.mes
@@ -102,6 +102,9 @@
 (pass-if "+" (seq? (+ 1 2 3) 6))
 (pass-if "*" (seq? (* 3 3 3) 27))
 (pass-if "/" (seq? (/ 9 3) 3))
+(pass-if "remainder" (seq? (remainder 11 3) 2))
+(pass-if "modulo" (seq? (modulo 11 3) 2))
+
 (pass-if "=" (seq? 3 '3))
 (pass-if "= 2" (not (= 3 '4)))
 (pass-if "if" (seq? (if #t 'true) 'true))