An indirect automatic blood pressure (BP) monitor utilizing the oscillometric principle and a microprocessor is now available for use in infants. This device was evaluated by comparing its systolic BP determinations with simultaneous Doppler systolic BP determinations in neonates and infants undergoing general anesthesia. Five determinations each were made in 125 babies who were grouped according to age. Correlation coefficients of the paired BP determinations were: in 27 premature neonates, r = 0.82; in 24 term neonates, r = 0.93; in 47 infants aged 5 to 13 weeks, r = 0.92; and in 27 infants aged 14 to 26 weeks, r = 0.94. The device was also evaluated by comparing its BP determinations with those of indwelling arterial lines present in 20 additional infants (five determinations each). Correlation coefficients were 0.96 for systolic determinations and 0.94 for diastolic determinations. No morbidity or significant technical problems were noted. It was concluded that the device is an accurate, safe, and easy noninvasive method for monitoring BP in infants.