BACKGROUND: We aim to determine clinical risk factors for postoperative complications in preterm infants with surgical necrotizing enterocolitis (NEC) or spontaneous intestinal perforation (SIP). METHODS: A retrospective cohort study of preterm infants with surgical NEC or SIP to compare clinical factors between those with and without postoperative complications. RESULTS: 78/109 (71.5%) infants had any complication following surgical NEC. Adhesions (20/35, 57.1%) and wound infection (6/35, 17.1%) were the most common single surgical complications. Patients with a single surgical complication (35/66, 53%) were significantly less likely to be exposed to antenatal steroids, more frequently had a jejunostomy, needed a central line longer, and had a longer length of stay than those without any surgical complication. Infants with > 1 surgical complication (43/71, 60.5%) included mainly females, and had AKI more frequently at NEC onset, lower weight z-scores and lower weight for length z- scores at 36 weeks PMA than those without any complications. On multinomial logistic regression, antenatal steroids exposure (OR 0.23 [CI 0.06, 0.84]; p = 0.027) was independently associated with lower risk and jejunostomy 4.81 (1.29, 17.9) was independently associated with higher risk of developing a single complication. AKI following disease onset (OR 5.33 (1.38, 20.6), P = 0.015) was independently associated with > 1 complication in surgical NEC/SIP infants. CONCLUSION: Infants with postoperative complications following surgical NEC were more likely to be female, have additional morbidities, and demonstrate growth failure at 36 weeks PMA than those without surgical complications. There was no difference in mortality between those with and without surgical complications.