Following an extensive survey into the requirements of agricultural aircraft operators, the company flew the prototype of the Cessna Model 188 AGwagon (later renamed AG Wagon) on 19 February 1965. A braced low-wing monoplane of all-metal construction, the new design had non-retractable tailwheel landing gear, with accommodation for the pilot in an enclosed cabin protected by a steel overturn structure. Power was provided by either a 172kW Continental IO-470-R or a 224kW Continental IO-520-D engine for the AGwagon 230 or AGwagon 300 respectively. Standard agricultural equipment included a 757-litre or 816kg capacity glassfibre hopper between the engine firewall and the cabin, and optional dusting or spraying equipment was available.

An increasing market for the AGwagon resulted in the introduction of a new model of this aircraft in late 1971; plus two additional versions designated as the AGpickup and AGtruck. The AGpickup was the basic model, a new name applied to the Continental O-470-R version of the original AGwagon; the Continental IO-520-D AGwagon was renamed AGwagon C and introduced a number of detail refinements; and the AGtruck was generally similar to the AGwagon C, except for the provision of a 1060-litre hopper plus a complete spray system and a wide range of equipment as standard. Of these three types the AGpickup was discontinued in 1976, and production of the AGwagon ended during 1981, after 1,589 had been built.

In 1979 Cessna introduced the AG Husky, a turbocharged version of the AGtruck (later AG Truck) powered by a 231kW TSIO-520-T engine giving all round improved performance. When production of both types ceased late in 1985, 386 AG Huskys had been delivered, alongside 1,949 AG Trucks.