Apnea commonly occurs in preterm infants, and may persist until discharge. Limited information on apnea characteristics and subsequent neurodevelopment is available. METHODS. Cohort follow-up study was performed on 164 unselected preterm infants (birth weight ≤ 1250 gm; gestational age ≤ 32 wk) discharged from two NICUs in Edmonton between 8/88 and 4/93. Infants thought to be ready for hospital discharge, and thought to be apnea free, were prospectively studied with 24-hour 4 channel recordings within 3 days before discharge. Multidisciplinary follow-up assessment was performed at 15 to 64(median 24) months of age. The mental and performance developmental scores were related to the severity of apnea (mean bradycardia [average decrease in heart rate] and mean desaturation [average decrease in oxygen saturation] during apneic spells), and frequency of apnea in individual birth weight groups (500-749 gm, 750-999 gm, 1000-1249gm). RESULTS Prevalence of apnea was 82% with 8% central, 42% obstructive and 50% mixed apneic spells. There were 31 (18.9%) disabled children; 12 (7.3%) were multiply disabled. Significant correlations were found between both indices of severity of apnea and developmental scores by univariate regression. The mean bradycardia of apnea was an independent predictor of both the mental and performance developmental scores in the 500-749 gm group (n=25), by multivariate regression. The duration of initial ventilation for respiratory distress syndrome, duration of oxygen supplement and severity of intraventricular hemorrhage were independent predictors of neurodevelopmental outcome.CONCLUSION While neurodevelopmental outcome is most closely associated with the duration of artificial ventilation and oxygen supplementation, and severity of intraventricular hemorrhage, increasing severity of predischarge apnea is associated with poorer neurodevelopment.