diff --git a/src/filter/src/iirfilt.proto.c b/src/filter/src/iirfilt.proto.c
index 3411a1f94..dc3b6f71b 100644
--- a/src/filter/src/iirfilt.proto.c
+++ b/src/filter/src/iirfilt.proto.c
@@ -238,7 +238,8 @@ IIRFILT() IIRFILT(_create_prototype)(liquid_iirdes_filtertype _ftype,
     float A[h_len];
 
     // design filter (compute coefficients)
-    liquid_iirdes(_ftype, _btype, _format, _order, _fc, _f0, _ap, _as, B, A);
+    if (liquid_iirdes(_ftype, _btype, _format, _order, _fc, _f0, _ap, _as, B, A) != LIQUID_OK)
+        return liquid_error_config("iirfilt_%s_create_prototype(), could not design filter", EXTENSION_FULL);
 
     // move coefficients to type-specific arrays (e.g. float complex)
     TC Bc[h_len];