The interactions of preterm infants with parents were compared with their interactions with nurses. Twenty-nine high-risk preterm infants who were a part of a larger longitudinal study of behavioral development were observed once weekly from 7 p. m. to 11 p. m. A single observation for each infant that contained a minimum of 2 min of parental care and 2 min of nursing care was selected for analysis. Results showed that nurses and parents provided different types of stimulation with nurses more likely to engage in procedural care and parents more likely to hold, talk to, move, and touch the infants affectionately. Infants showed more sleep-wake transition, large body movements, and jitters when with nurses and more active sleep and more smiles when with parents. Similar differences were found when parents and nurses were just holding or touching the infants, but no differences in infant responses were seen during feeding or changing. Thus, the different infant behavioral responses appeared to result primarily from the different stimulation provided by parents and nurses. Implications of these findings for research and clinical practice are discussed.