Pneumogram (PG) recordings were performed in 87 very low birthweight (VLBW) asymptomatic infants just prior to hospital discharge to determine the relationships between: 1) a prior history of apnea of prematurity (AOP) and cardiorespiratory pattern; and 2) cardiorespiratory pattern at hospital discharge and postconceptional age. Apnea density (A6/D%) and longest apnea were significantly greater in those with (n = 66), versus without (n = 21) a prior history of AOP (P less than 0.05 and P less than 0.01, respectively). Although PG values for the 21 VLBW infants without a prior history of AOP did not differ significantly from those of full-term infants, for the 66 VLBW infants with a prior AOP history A6/D% (P less than 0.01), episodes of periodic breathing (P less than 0.05) and longest apnea (P less than 0.001) were significantly greater compared with full-term infants. Postconceptional age was significantly less in the VLBW infants with A6/D% values above, compared with those within the 95th percentile for normal infants (median age, 36 and 37.5 weeks; P = 0.01). Therefore, respiratory pattern abnormalities in asymptomatic VLBW infants ready for hospital discharge are related to a prior history of AOP and may be significantly higher than in full-term infants at the postconceptional ages at which hospital discharge now tends to occur.