INTRODUCTION: Administration of parenteral medications may cause pain in infants. This study aimed to assess the efficacy of a nursery rhyme in increasing the comfort of infants after vaccination. METHODS: Infants who were brought to six barangay health centers for vaccination were recruited. Infants from three barangay health centers were randomly assigned to the experimental group, while infants from the other three were assigned to the control group. A Filipino nursery rhyme Tatlong Bibe was played to the experimental group. The comfort of each infant was then assessed by a pediatrician prior to, immediately after, and two minutes post-vaccination using the COMFORTB scale. Results were analyzed using independent t-tests. RESULTS: Prior to vaccination, the control and experimental groups had mean COMFORT-B scores of 12.46 and 12.74 (p = 0.634), respectively. The immediate post-vaccination mean COMFORT-B scores were 22.14 and 21.63 (p = 0.420), while the 2 minutes post-vaccination mean COMFORT-B scores were 16.40 and 16.49 (p = 0.927), respectively. There were no significant differences between groups for the three determinations. CONCLUSION Based on the study results, the nursery rhyme had no significant effect on the comfort of infants after vaccination.