Respiratory syncytial virus (RSV) is the leading viral pathogen responsible for bronchiolitis and pneumonia in infants. We assessed palivizumab prophylaxis compliance for infants in Puerto Rico. We retrospectively studied data from 868 infants (409 females, 459 males) during the 2009-2010 RSV season. The infants had a mean gestational age of 33 weeks (range 23-41) and a mean birth weight of 1,767 g (range 509-4,120). Only 74 % of the infants with indications received prophylaxis. The main reasons for noncompliance were non-approval by the medical insurance (53 %), parents' unavailability (31 %), and infant sickness (11 %). Infants with the government medical insurance were more likely to be denied prophylaxis and to receive fewer doses. Parents need to be educated on the importance of RSV prophylaxis. Physicians should be aware that many infants are not being dosed appropriately and that strategies need to be established to improve compliance.