Doppler echocardiographic studies were performed in 380 consecutive patients with 415 normally functioning artificial valves to establish normal Doppler characteristics for each type of prostheses used in our institution, with particular reference to Starr-Edwards valves, and to serve as control studies for future assessment. None of the patients were in heart failure at the time of the study. Peak transaortic velocities (m . s-1) were higher and effective orifice areas (cm2) smaller in mechanical valves as a whole, when compared with bioprostheses (P < 0.01); 2.7 ± 0.7 and 1.4 ± 0.55 for Starr-Edwards, 2.7 ± 0.6 and 7.5 ± 0.6 for Bjork-Shiley, 1.8 ± 0.1 and 1.5 ± 0.6 for Duromedics and 1.5 ± 0.06 and 2 ± 0.12 for bioprostheses, respectively. In the mitral position, the average peak diastolic velocities (m . s-1) and pressure half-times (ms) were higher in mechanical valves, but there was a large overlap between the various types and sizes of prostheses (P = NS); 1.6 ± 0.3 and 98 ± 25 for Starr-Edwards, 1.4 ± 0.3 and 88 ± 26 for Bjork-Shiley, 1.8 ± 0.1 and 75 ± 5 for Duromedics and 1.5 ± 0.3 and 90 ± 20 for bioprostheses, respectively. There was an inverse relation between valve size and pressure half-time for Starr-Edwards prostheses (P < 0.01). Doppler flow characteristics in mechanical valves where similar in patients with normal and dysfunctioning prostheses. Valvular or myocardial dysfunction could best be ascertained when early postoperative studies were available for comparison. No single Doppler measurement was able to separate normal from abnormal prosthetic valve function, so it is recommended that patients have a comprehensive baseline cross-sectional and Doppler examination before postoperative discharge so that each will have a personal 'Doppler identity '. This will help the recognition of possible future prosthetic valve or myocardial deterioration. © 1992 The European Society of Cardiology.