A general purpose instrumentation and data logging system was developed for a 97 kW agricultural tractor for use in field research on tractor and implement performance. The tractor was fitted with a set of transducers to measure fuel consumption, engine, wheel, and ground speed, front and rear axle torque and weight, and forces in the three-point hitch. Transducer signals were isolated, amplified, and filtered by signal conditioners, and recorded by a microcomputer-based data logger. Flexible software was developed to control the data logger. The software had provision for a wide range of sampling rates and real-time graphic display of up to eight data channels. The system hardware and software were designed to accommodate future expansion with additional transducers on the tractor or implement. A cab extension was built on the side of the existing tractor cab to house the instrumentation system and data logger operator.