diff --git a/src/finn/transformation/fpgadataflow/convert_to_hls_layers.py b/src/finn/transformation/fpgadataflow/convert_to_hls_layers.py
index 753dbb0f87a877f69a24bb520d09a173925cafd4..9153124973702ea559d44b05346d0210d83d44b6 100644
--- a/src/finn/transformation/fpgadataflow/convert_to_hls_layers.py
+++ b/src/finn/transformation/fpgadataflow/convert_to_hls_layers.py
@@ -1662,6 +1662,7 @@ class InferConcatLayer(Transformation):
                     ElemsPerStream=elems_per_stream,
                     inputDataType=dt0.name,
                     numInputVectors=inp_vec,
+                    inFIFODepths=[2] * len(node.input),
                 )
                 graph.node.insert(node_ind, new_node)
                 # remove old node