An instrumentation system to measure tractor field performance was developed and refined. The system consisted of four sections: transducers, a signal conditioner, a data acquisition system, and a data analysis system;A John Deere 4430 tractor was equipped with the instrumentation system. The transducers measured fuel flow, travel speed, wheel rotational speed, drawbar pull, and rear axle torque. The data acquisition system included an interface board, an AIM 65 microcomputer and a digital cassette recorder (Techtran 817). The microcomputer program was developed with an assembly language so that the system could display and record the data including time, fuel flow rate, travel speed, distance traveled, wheel slip, drawbar pull, and axle torque. The data collected in the field were dumped to and analyzed by a main frame computer. This system functioned relatively well, but still needed some modifications;To improve the system, an RM 65 microcomputer was substituted for the AIM 65. The RM 65 was more compact in size and flexible in design. A computer programmable signal conditioner with 16 dual channels was built to replace the original signal conditioner. To develop the microcomputer program, an inexpensive software development system was constructed;A three-point hitch dynamometer was designed and constructed to measure forces on mounted implements. This dynamometer was based on a three-point hitch quick-attaching coupler, and measured forces in three orthogonal directions. The instrumentation system was used to collect data on tractor field performance.