Breast milk is widely recognized as the best source of nutrition for both full term and premature babies. We aimed to identify clinical results of the implementation of a breast milk bank for premature infants under 37 weeks in a level III hospital. 722 neonates under 37 weeks, hospitalized in the Neonatal intensive care unit (ICU), who received human breast milk from the institution's milk bank 57% (n = 412) vs. mixed or artificial 32% (n = 229), at day 7 of life. An exploratory data analysis was carried out. Measures of central tendency and dispersion were used, strength of association of odds ratio (OR) and its confidence intervals (95% confidence interval (CI)). 88.5% had already received human milk before day 7 of life. Those who received human milk, due to their clinical condition, had 4 times a greater chance of being intubated (OR 4.05; 95% CI 1.80-9.11). Starting before day 7 of life decreases the opportunity to develop necrotizing enterocolitis by 82% (adjusted odds ratio (ORa) 0.18; 95% CI 0.03-0.97), intraventricular hemorrhage by 85% (ORa 0.15; 95% CI 0.06-0.45) and sepsis by 77% (ORa 0.23; 95% CI 0.15-0.33). Receiving human milk reduces the probability of complications related to prematurity, evidencing the importance that breast milk banks play in clinical practice.