diff --git a/extra/cuda/demos/prefix-sum/prefix-sum.factor b/extra/cuda/demos/prefix-sum/prefix-sum.factor
index 1ea8d83b44..daa1c6c674 100644
--- a/extra/cuda/demos/prefix-sum/prefix-sum.factor
+++ b/extra/cuda/demos/prefix-sum/prefix-sum.factor
@@ -8,6 +8,7 @@ CUDA-LIBRARY: prefix-sum vocab:cuda/demos/prefix-sum/prefix-sum.ptx
 CUDA-FUNCTION: prefix_sum_block ( uint* in, uint* out, uint n ) ;
 
 :: cuda-prefix-sum ( -- )
+    init-cuda
     0 0 [
         ! { 1 1 1 } { 2 1 } 0 3<<< prefix_sum_block
     ] with-cuda-context ;