Introduction: Necrotizing enterocolitis (NEC) is a major cause of mortality among premature babies. It has no definitive pathogenesis and no specific treatment. Its prevention remains the most important intervention till now. 
Aim of the work: To detect the impact of using mother's own milk to feed preterm babies (< 37 weeks) on necrotizing enterocolitis, occurrence of signs of feeding intolerance, sepsis and mortality.  
Methods: This prospective cohort study enrolled 250 preterm babies (< 37 weeks) whose gestational ages ranged from 27-36 weeks who were admitted to the neonatal intensive care unit (NICU) of Kasr Al-Ainy Hospital, Cairo University soon after birth. Mothers with no contraindication to breast feeding were included in the "case" group and the others were included in "control" group. 
Results: The mean± SD gestational age of the case group (120 preterm) was 33.12 ± 1.63 weeks and of the control group (130 preterm) was 32.17 ± 1.95 weeks. The mean birth weights of the case and control groups were 1.86 ± 0.49 and 1.55 ± 0.32 kgs, respectively (p= 0.000). The case group showed significant decrease in the incidence of NEC (5% in the case group versus 13% in the control group (p= 0.027). Sepsis incidence also decreased among patients in the case group (37.5% in the case group versus 60% in the control group (p= 0.00). There was no significant difference between the two groups regarding time at which trophic feeding was started but the study group showed significantly shorter duration to reach both minimal enteral nutrition (20cc /kg) (6.85 ± 3.16 days versus 11.20 ± 7.05 days in the control group) (p= 0.000) and full feeds (10.60 ± 3.94 days versus 15.47 ± 8.85 in the control group) (p= 0.000). The mean duration of total parenteral nutrition was significantly shorter in the case group (p= 0.020). The difference between the need for antibiotics in both groups was insignificant (p= 0.353). However, the duration of antibiotic therapy was significantly shorter in the case group (p= 0.000).
Conclusion: Preterm mother's own milk feeding (not necessarily exclusively) proved to be protective against NEC, sepsis and poor outcome.