diff --git a/litex/soc/interconnect/csr.py b/litex/soc/interconnect/csr.py
index 4ee7a41c7..4165dbd24 100644
--- a/litex/soc/interconnect/csr.py
+++ b/litex/soc/interconnect/csr.py
@@ -340,6 +340,7 @@ class GenericBank(Module):
         self.simple_csrs = []
         for c in description:
             if isinstance(c, CSR):
+                assert c.size <= busword
                 self.simple_csrs.append(c)
             else:
                 c.finalize(busword)