BACKGROUND: We evaluated the outcomes of patients undergoing surgical repair of partial atrioventricular septal defect (AVSD) and analyzed the effect of age on outcome. METHODS: In this single-center retrospective study, we included all children who underwent repair of partial AVSD between 1990 and 2014. We divided the patients into 4 age quartiles (first quartile: 0-0.75 years, n = 22; second quartile: 0.75-1.5 years, n = 21; third quartile: 1.5-3.75 years, n = 22; and fourth quartile: >3.75 years, n = 21). These quartiles were evaluated for their association with the time-to-event outcomes of survival, freedom from left atrioventricular valve regurgitation (LAVVR), and freedom from reoperation using log-rank analysis. RESULTS: During the study period, 86 patients underwent partial AVSD repair at a median age of 1.5 years. There were no operative deaths and 2 late deaths (unknown cause and trauma). There were 13 reoperations. The most common cause of reoperation was left ventricular outflow tract obstruction (LVOTO) (5 patients [first quartile, 2 cases; second quartile, 1 case; third quartile, 2 cases, and fourth quartile, 0 cases]). LAVV reoperation for insufficiency or stenosis was performed in 4 patients (first quartile, 1 case; second quartile, 1 case; third quartile, 1 case; and fourth quartile, 1 case). Two patients underwent pacemaker placement (second quartile, 1 case and fourth quartile, 1 case). There were no statistically significant differences in the most common complications-LVOTO, LAVVR, and AV heart block-between the 4 age quartiles. Median follow-up was 7.1 years (interquartile range [IQR], 0.8-11.4 years). On echocardiography, 72 patients (84%) had less than or equal to mild LAVVR, 8 (9%) patients had mild to moderate LAVVR, 5 (6%) patients had moderate LAVVR, and 1 (1%) patient had severe LAVVR. Age at repair had no significant association with degree of late AV valve insufficiency. CONCLUSIONS: Results of partial AVSD repair at a median age of 1.5 years are excellent. Operating at this age is not associated with increased mortality, reoperation, or LAVVR.