PZL.46 Sum (catfish) was a projected light bomber of the Polish Air Force before World War II, which did not proceed beyond prototype stage. The first prototype of PZL.46 Sum flew in August 1938. In March 1939 the PZL.46 was ordered for a serial production. The Polish Air Force planned to buy 160 aircraft in a variant PZL.46A. The first aircraft were to be delivered in early 1940.