Parenting a newborn infant has been identified as a significant stressor, and parenting a sick infant evokes an even greater stress. This study evaluated the differential impact of parenting infants with interrupted infantile apnea vs. extremely low birth weight infants. These infants were compared to normal infants on the Bayley Scales of Infant Assessment and the Parenting Stress Index when the infants were 6 months old. Significant effects on the mental index revealed that the low birthweight infants performed more poorly than did the other groups. A stepwise multiple discriminant analysis on the Parenting Stress Index suggested that child adaptability, maternal restrictions, isolation, and health were significant stressors. Mothers of apneic infants were affected most severely by their child's illness. The lower educational level of these mothers may have influenced these findings.