Background: The incidence of necrotizing enterocolitis (NEC) and possibly also of sepsis is lower in preterm infants fed their own mother’s milk (hereafter ‘mother’s milk’) compared with formula-fed infants. It is unclear whether this is caused by the protective properties of breast milk or by the absence of cow’s milk. Especially in early life, mother’s milk is often unavailable to preterm infants, while minimal enteral nutrition is initiated immediately. Objectives: To determine whether there is an association between intake of mother’s milk during the first days of life and the combined outcome of sepsis, NEC and death over a prolonged period. Methods: Retrospective study in infants with a birth weight <1,500 g. Intake of mother’s milk and formula during the first 10 days of life was recorded. The occurrence of sepsis, NEC and death was registered during the first 60 days. Data were analysed using Cox regression analysis, taking confounders into account. Results: In total, 349 infants were included. Intake of mother’s milk during the first 5 days of life was associated with a lower incidence of NEC, sepsis and/or death during the first 60 days of life (hazard ratio (HR) in the category 0.01–50% intake of mother’s milk: 0.49, 95% confidence interval (CI) 0.28, 0.87; HR in the category 50.01–100% intake of mother’s milk: 0.50, 95% CI 0.31, 0.83, both compared to no mother’s milk). During days 6–10, the protective effect was only present if >50% of the total intake was mother’s milk (HR = 0.37, 95% CI 0.22, 0.65). Conclusion: The type of enteral nutrition during the first 10 days of life is associated with the risk of NEC, sepsis and/or death during the first 60 days of life.