In an attempt to minimize the selection bias inherent in reporting the outcome of premature infants from a particular neonatal intensive care unit, this study presents data on all 294 live births 501 to 1,500 gm birth weight born to residents in the Hamilton-Wentworth region during 1973-78. The survival rate was 31.9% in infants less than or equal to 1,000 gm and 82.6% in infants between 1,001 to 1,500 gm. In all, 184 infants (62.6%) were discharged alive and 37 of these had weight less than or equal to 1,000 gm. The mean BW of the survivors was 1,216 +/- 214 gm and the mean gestation was 30.0 +/- 2.9 weeks, with 18.0% being small-for-gestational age. Neurologic handicaps including cerebral palsy, hydrocephalus, microcephaly, blindness, deafness, and mental retardation occurred in 30/179 (16.8%) survivors. The incidence of neurologic handicaps was 30% among babies who received IPPV versus 10% in those who did not. Within the IPPV and non-IPPV groups, there were no significant differences in handicap rates by 500 gm BW class.