A Tektronix 4956 graphics tablet with a Tektronix 4051 graphics computer was used to digitize hard copy recordings obtained in a study of the effects of antihypertensive drugs on blood velocity. Hard Copy spectral displays (sonagraphs) of Doppler audio blood velocity signals were digitized, givingpeak height (peak velocity), mean height (mean velocity), slope (acceleration) and area (stroke volume index). Coefficients of variation, even for inexperienced operators were 1–5%, except for slope (11%). For systolic time intervals, data was entered by touching a magnetic pencil to time landmarks on a recording of ECG, carotid pulse and phonocardiogram. Mean and standard deviation of PEP/LVET and 1/PEP2 were printed out after entering 10 successive cardiac cycles. Co-efficients of variation for inexperienced operators were 2–3%, much less than for fully manual methods, time involved was 1/10 that required for manual measurement and calculation of Systolic Time Intervais (STIs). The methods presented permit inexpensive, convenient access to computer processing of cardiovascular signals.