diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,5 +1,8 @@
 # Changelog for barbies
 
+## 1.1.2.1
+  - Uploaded 1.1.2.0 was broken (missing `btraverseC`)
+
 ## 1.1.2.0
   - Add `traverseC` (Ole Krüger).
   - Fix typo in ProductB laws (thanks to Ben Radford).
diff --git a/barbies.cabal b/barbies.cabal
--- a/barbies.cabal
+++ b/barbies.cabal
@@ -1,5 +1,5 @@
 name:           barbies
-version:        1.1.2.0
+version:        1.1.2.1
 synopsis:       Classes for working with types that can change clothes.
 description:    Types that are parametric on a functor are like Barbies that have an outfit for each role. This package provides the basic abstractions to work with them comfortably.
 category:       Data-structures
diff --git a/src/Data/Barbie.hs b/src/Data/Barbie.hs
--- a/src/Data/Barbie.hs
+++ b/src/Data/Barbie.hs
@@ -82,6 +82,7 @@
   , AllBF
     -- ** Utility functions
   , bmapC
+  , btraverseC
 
     -- * Products and constaints
   , ProductBC(bdicts)
@@ -108,7 +109,7 @@
 
 where
 
-import Data.Barbie.Internal.Constraints(ConstraintsB(..), AllBF, bmapC)
+import           Data.Barbie.Internal.Constraints (AllBF, ConstraintsB (..), bmapC, btraverseC)
 import qualified Data.Barbie.Internal.Constraints as Deprecated
 
 import Data.Barbie.Internal.Functor(FunctorB(..))
diff --git a/src/Data/Barbie/Constraints.hs b/src/Data/Barbie/Constraints.hs
--- a/src/Data/Barbie/Constraints.hs
+++ b/src/Data/Barbie/Constraints.hs
@@ -31,6 +31,7 @@
   , ConstraintsB(..)
   , ProductBC(..)
   , bmapC
+  , btraverseC
 
   , AllBF
   , ClassF
diff --git a/src/Data/Barbie/Internal/Constraints.hs b/src/Data/Barbie/Internal/Constraints.hs
--- a/src/Data/Barbie/Internal/Constraints.hs
+++ b/src/Data/Barbie/Internal/Constraints.hs
@@ -5,6 +5,7 @@
 module Data.Barbie.Internal.Constraints
   ( ConstraintsB(..)
   , bmapC
+  , btraverseC
   , AllBF
 
   , CanDeriveConstraintsB
@@ -21,8 +22,9 @@
 
 where
 
-import Data.Barbie.Internal.Dicts   (ClassF, Dict (..), requiringDict)
-import Data.Barbie.Internal.Functor (FunctorB (..))
+import Data.Barbie.Internal.Dicts       (ClassF, Dict (..), requiringDict)
+import Data.Barbie.Internal.Functor     (FunctorB (..))
+import Data.Barbie.Internal.Traversable (TraversableB (..))
 
 import Data.Functor.Compose (Compose (..))
 import Data.Functor.Const   (Const (..))
@@ -109,6 +111,14 @@
     go :: forall a. (Dict c `Product` f) a -> g a
     go (d `Pair` fa) = requiringDict (f fa) d
 
+-- | Like 'btraverse' but with a constraint on the elements of @b@.
+btraverseC
+  :: forall c b f g h
+  .  (TraversableB b, ConstraintsB b, AllB c b, Applicative g)
+  => (forall a. c a => f a -> g (h a))
+  -> b f
+  -> g (b h)
+btraverseC f b = btraverse (\(Pair (Dict :: Dict c a) x) -> f x) (baddDicts b)
 
 -- | Similar to 'AllB' but will put the functor argument @f@
 --   between the constraint @c@ and the type @a@. For example:
diff --git a/test/Spec.hs b/test/Spec.hs
--- a/test/Spec.hs
+++ b/test/Spec.hs
@@ -11,10 +11,11 @@
 import Barbies
 import BarbiesW
 
-import Data.Barbie (bfoldMap, bmapC, buniqC)
-import Data.Barbie.Bare(Covered)
-import Data.Functor.Const(Const(..))
-import Data.Functor.Identity(Identity(..))
+import Data.Barbie           (bfoldMap, bmapC, btraverseC, buniqC)
+import Data.Barbie.Bare      (Covered)
+import Data.Functor.Const    (Const (..))
+import Data.Functor.Identity (Identity (..))
+import Data.Monoid           (Sum (..))
 
 main :: IO ()
 main
@@ -187,6 +188,12 @@
           [ testCase "Record1" $
                 bmapC @Num (fmap (+1)) (Record1 (Identity 0))
                     @?= Record1 (Identity 1)
+          ]
+        , testGroup
+          "btraverseC"
+          [ testCase "Record1" $
+                btraverseC @Num (\inner -> (Sum @Int 1, fmap (+ 1) inner)) (Record1 (Identity 0))
+                    @?= (Sum 1, Record1 (Identity 1))
           ]
         , testGroup
           "buniqC"