BACKGROUND: Complications related to epicardial pacemakers in infants have been reported, though limited data are available on their incidence and associated risk factors. OBJECTIVE: The hypothesis of the study is that younger, smaller patients and larger devices would be associated with complications in neonates and infants. METHODS: This is a retrospective study of all patients at a single center receiving an epicardial pacemaker at =12 months of age (1996-2015). Patient and device characteristics were obtained. Characteristics of patients with and without complications were compared. RESULTS: There were 86 patients with a median age of 73 days (interquartile range 13-166 days), of whom 12 (14%) had a complication. Eight (9%) needed surgical intervention, of whom 5 (6%) required explantation. Younger age (9 days vs 89 days; P = .01) and lower weight (2.91 kg vs 4.44 kg; P = .004) at implantation were associated with complications. Device characteristics were not statistically different. Patients =3 kg in weight and/or <5 days of age had an odds ratio of 18.1 (3.6-91.2; P < .001) for developing a complication with a negative predictive value (NPV) of 97%. Regardless of weight, patients aged >21 days were found to be at lower risk with an NPV of 96%; and regardless of age, patients weighing >4 kg had an NPV of 98%. CONCLUSION: Young age and low weight at the time of implantation are risk factors for complications, while device characteristics appear to play a minor role. Reserving pacemaker implantation for patients >3 kg in weight and 5 days of age may predict patients at low risk of developing complications.