diff --git a/lib/std/core/maybe.kk b/lib/std/core/maybe.kk
index d5fc33284..0cd03ab54 100644
--- a/lib/std/core/maybe.kk
+++ b/lib/std/core/maybe.kk
@@ -42,6 +42,11 @@ pub fun map( m : maybe<a>, f : a -> e b ) : e maybe<b>
     Nothing -> Nothing
     Just(x) -> Just(f(x))
 
+pub fun flatmap( m : maybe<a>, f : a -> e maybe<b> ) : e maybe<b>
+  match m
+    Nothing -> Nothing
+    Just(x) -> f(x)
+
 pub fun (||)( m1 : maybe<a>, m2: maybe<a> ) : maybe<a>
   match m1
     Nothing -> m2
diff --git a/lib/std/core/maybe2.kk b/lib/std/core/maybe2.kk
index 36417f67b..80bbf7a48 100644
--- a/lib/std/core/maybe2.kk
+++ b/lib/std/core/maybe2.kk
@@ -43,6 +43,11 @@ pub fun map( m : maybe2<a,b>, f : (a,b) -> e (c,d) ) : e maybe2<c,d>
     Just2(x,y)  -> match f(x,y)
                      (fx,fy) -> Just2(fx,fy)
 
+pub fun flatmap( m : maybe2<a,b>, f : (a,b) -> e maybe2<c,d> ) : e maybe2<c,d>
+  match m
+    Nothing2    -> Nothing2
+    Just2(x,y)  -> f(x,y)
+                     
 pub fun (||)( m1 : maybe2<a,b>, m2: maybe2<a,b> ) : maybe2<a,b>
   match m1
     Nothing2 -> m2