On 2 March 1952 Piper flew the prototype of a new twin-engine aircraft which it then identified as the Piper PA-23 Twin-Stinson. A cantilever low-wing monoplane of all-metal construction, it had a tailplane set high on the fuselage and mounting endplate fins and rudders, retractable tricycle landing gear and an enclosed cabin seating four in two pairs, and was powered by two 112kW Avco Lycoming O-320 flat-four engines in wing-mounted nacelles. The tail unit was very soon replaced by a conventional tailplane with centrally mounted single fin and rudder, and it was in this form that it entered production in early 1954 as the PA-23 Apache, later designated PA-23 Apache 150. The type continued in production as the Apache until 1965, by which time 2,166 had been built, including 1,231 examples of the first production version. The original model was followed in 1958 by the PA-23 Apache 160 with 119kW O-320-B engines, and with some interior revisions so that it was classed as a four/ five-seat aircraft (816 built), and in 1962 by the similar PA-23 Apache 235, which introduced swept tail surfaces and 175kW Avco Lycoming O-540-B1A5 flat-six engines (119 built).

With sales of the Apache 235 declining, Piper developed an improved version of this aircraft which introduced a 186kW O-540 engine and provided six-seat capacity. This entered production under the designation PA-23-250 Aztec in 1959-60, the US Navy acquiring 20 of these aircraft for use in a utility role, designating them UO-1, changed to U-11A in 1962. The Aztec was built until early 1982 when production was suspended. In finaj production form the type had the designation PA-23-250 Aztec F, and was available also as the generally similar PA-23T-250 Turbo Aztec F which differed by having Avco Lycoming TIO-540 engines with a Garrett turbo-charging system.