Infants seek contingent, companionable interactions with others. Infants in a Neonatal Intensive Care Unit (NICU), while receiving care that optimizes their chances of survival, often do not have the kind of interactions that are optimal for their social development. Live music therapy (MT) with infants is an intervention that aims for contingent, social interaction between therapist and infant. This study, with a limited numbers of infants, examined the effectiveness of an MT intervention in the NICU at The Royal Children's Hospital Melbourne. Two groups of late pre-term and full-term infants were recruited to the study; one was given MT and the other was not. A healthy group of infants not given MT served as an additional control. The effect of MT was indexed using two measures reflecting infant social engagement: the Neurobehavioral Assessment of the Preterm Infant (NAPI) and the Alarm Distress Baby Scale (ADBB). Results suggest that the MT intervention used at The Royal Children's Hospital Melbourne supports infants' neurobehavioral development. In particular, hospitalized infants who received MT were better able to maintain self-regulation during social interaction with an adult, were less irritable and cried less, and were more positive in their response to adult handling, when compared with infants who did not receive the intervention. These are important prerequisites for social interaction and development. Further and larger scale research using MT with this population is indicated.