Background: Nonpharmacological interventions are needed to reduce pain during vaccine administration in infants. Purpose: To determine the effect of the Buzzy device, which is a combination of cold and vibration, on pain during measles-mumps-rubella (MMR) vaccine administration in 12-month-old infants. Methods: A prospective randomized controlled experimental research design was used. Results: A total of 60 infants were included in the study. During and after vaccine injection, pain scores of infants who had the Buzzy device were significantly lower than those of infants in the control group (P = .001). Conclusions: Buzzy application may be an effective method in reducing pain during MMR vaccine administration. Use of the device is recommended for infants receiving vaccinations.