The hydrodynamic testing of prosthetic heart valves in the laboratory under pulsatile flow conditions remains the only way of obtaining detailed information about valve function. Test procedures have become increasingly sophisticated, with a variety of different test conditions and detailed analysis of the pressure and flow signals. A computerized data acquisition system has been developed for use with the Glasgow pulsatile flow test apparatus. The computer collects seven signals from the test rig over a period of 20 s, and calculates the average waveform for each signal. Standard parameters, such as mean pressure differences, mean flows, regurgitant volumes and energy losses, are calculated automatically. The complexity of the analysis and the need for standardized documentation makes computerization essential. The system has been used extensively for function tests on over 160 prosthetic heart valves.