A John Deere farm tractor model 4430 H was instrumented to monitor forward velocity, slip, area operated by implement, rate of fuel consumption, total fuel consumption, theoretical field time and total field time. Two magnetic pickups each with a ferrous gear were used to monitor the angular velocity of the right front and rear wheels. The fuel consumption was monitored with a single turbine flow transducer. An intermediate float tank system was used to accommodate the return fuel from the injector pump and injectors. A micro switch was also used to detect the operating position of the implement. The transducers attached to the tractor did not require any major alteration of the tractor system or restrict its operation;A single board microcomputer tractor performance monitor based on Intel 8035 single chip microcomputer was developed to monitor the inputs of the transducers and controls and to calculate and display the values of the monitored parameters. The developed tractor performance monitor had the following capabilities: (1) 2048 8-bit words of program memory; (2) 64 8-bit words of data memory; (3) one 8-bit data input port; (4) two 3-digit and three 2-digit displays; (5) single step unit; (6) single 5-volt power supply; and (7) expansion capabilities with (i) 2048 8-bit words of program memory, (ii) 256 8-bit words of data memory, and (iii) virtually unlimited input/output ports;The instrumented tractor was tested with a chisel plow and a tandem disc harrow in a slightly wet combine harvested corn field. All the transducers functioned properly and proved to be reliable under field conditions. The system also was easy and simple to use without restricting operator movement. The operator starts and stops the data acquisition of the monitor with an easily-reached switch.