In this article we report the survival and morbidity rates for all live-born infants weighing 501 to 1000 gram at birth and born to residents of a defined geographic region from 1977 to 1980 (n = 255) compared with 1981 to 1984 (n = 266). During these periods, there were no changes in the proportion of infants delivered at the tertiary care center or community hospitals (171/84 vs 194/72); use of the tertiary care center increased only slightly, from 84% to 91%; and changes in neonatal management were mainly in improvements in diagnostic and monitoring techniques. When infants were grouped according to birth weights in 100 gm increments, survival improved significantly only for infants weighing between 501 and 600 gm at birth (2% vs 20% p less than 0.001). There were no differences in the overall survival rates to hospital discharge (46% vs 48%). The prevalence of neurosensory impairments was 24% in period 1 and 17% in period 2. There was a significant improvement in the proportion of infants considered to have disabilities by a functional classification assigned at 3 years corrected age (50% vs 27%, p less than 0.001), but only for infants weighing more than 800 gm at birth (49% vs 22%, p less than 0.001). Infants delivered at the community hospitals had a higher prevalence of neurosensory impairments compared with infants delivered at the tertiary care center (period 1, 35% vs 21%, not significant; period 2, 37% vs 14%, p less than 0.05). These data are encouraging; further efforts should be directed toward assessing which, if any, components of perinatal care are contributing to the improvement in morbidity rates.