diff --git a/src/caffe/layers/base_data_layer.cu b/src/caffe/layers/base_data_layer.cu
index 56439bc506a..ff6e412aba6 100644
--- a/src/caffe/layers/base_data_layer.cu
+++ b/src/caffe/layers/base_data_layer.cu
@@ -20,7 +20,9 @@ void BasePrefetchingDataLayer<Dtype>::Forward_gpu(
     caffe_copy(batch->label_.count(), batch->label_.gpu_data(),
         top[1]->mutable_gpu_data());
   }
-
+  // Ensure the copy is synchronous wrt the host, so that the next batch isn't
+  // copied in meanwhile.
+  CUDA_CHECK(cudaStreamSynchronize(cudaStreamDefault));
   prefetch_free_.push(batch);
 }