A simple and accurate computer simulation method was developed to evaluate the geometrical parameters of disk-type artificial heart valves from cinefluorographic recordings. In vitro valve models with preset occluder angles were used to test the accuracy of the method. Linear regression analysis produced slope 1.00055 and intercept 0.0402, with r = 0.999. In vivo reproducibility was tested through repeated measurements, taken several weeks apart, of OMS valves in situ. Regression with slope 1.02 and intercept -0.95, r = 0.95 were found. © Lippincott-Raven Publishers.