The Merzario A4 was a racecar designed by Giampaolo Dallara.

The car was raced during the 1979 season of Formula One being driven by Artuno Merzario. The car was entered in seven races (British GP, German GP, Austrian GP, Dutch GP, Italian GP, Canadian GP and USA E GP). The car failed to qualify for any of the races which it was entered in.

The car was fitted with a Ford Cosworth DFV V8engine and rode on Goodyear tyres. The A4 had an aluminium monocoque chassis and was fitted with a Hewland FGA 400.

The car was not a success and so was dropped.