Complications related to epicardial pacemakers in infants have been reported, though limited data are available on their incidence and associated risk factors. The hypothesis of the study is that younger, smaller patients and larger devices would be associated with complications in neonates and infants. 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. 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%. 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.