Persistent pulmonary hypertension of the newborn ( PPHN ) has become a more commonly recognized problem in neonatal intensive care nurseries. In 62 neonates, 27 from 1980 and 35 from 1981, we compared classification, methods of diagnosis, modes of therapy, and survival. Thirty neonates (48%) had primary and 32 (52%) had secondary PPHN . Overall survival was 71% with significant differences in primary v secondary PPHN . Survival was also higher in 1981 than 1980 and was related to earlier diagnosis and to the more rapid initiation of therapy.