Introduction: Complications related to epicardial cardiac rhythm devices in infants have been reported though limited data are available regarding their incidence and associated risk factors. Hypothesis: Epicardial pacemakers carry a risk for significant complications which is associated with patient and device characteristics. Methods: Retrospective study of all patients at a single center receiving an epicardial pacemaker at ≤12 months of age at time of implant. Patient characteristics: weight, length, BSA, reason for implantation, prematurity, congenital heart disease and concomitant surgery were obtained. Device characteristics: height, width, length, thickness, mass and volume were also obtained. Wilcoxon Rank-Sum and Fisher’s exact tests were used to compare patient and device characteristics with and without major complications (any re-admission after implant). Using identified characteristics associated with complication, pre-implantation cutoffs for high and low risk for complications were established. Results: Eighty-six patients were identified, age 73 d (IQR 13-166); 12 (14%) had a major complication, 7 (8%) needed surgical intervention (6 for wound dehiscence and 1 for pericardial effusion) and 3 (3%) required whole system explantation. Younger age (9 vs 89 d, p=0.01), lower weight (2.91 vs 4.44 kg, p=0.004) and lower BSA (0.19 vs 0.24 m 2 , p=0.03) were associated with major complications. Other patient characteristics were not statistically different. Device height, thickness, mass, volume and dual vs. single chamber system did not differ between groups; however device width differed in patients with complications (p=0.02). Based on these data, a cutoff of >3 kg and ≥ 6 days of age was established as lower risk. Patients with weight ≤ 3 kg and/or <6 days old had an OR of 18.1 (3.6-91.2, p<0.001) for developing a major complication. Using this model resulted in a sensitivity of 83% and positive and negative predictive values of 38% and 97%, respectively. Conclusions: Young age and low weight at the time of implant are risk factors for major complications while device characteristics appear to play a minor role. Using weight and age cutoffs of 3 kg and 6 days respectively may predict patients at very low risk for developing major complications.