Abstract Introduction Very low birth weight (VLBW) neonates ( 5 days) increases an infant’s risk for necrotizing enterocolitis, late onset sepsis, colonization or infection with resistant organisms, and death. The aim of this study is to describe clinical and laboratory factors that influence the length of initial antibiotic courses in VLBW neonates. Methods Demographics, perinatal factors, and neonatal clinical and laboratory data were compared in a single-center retrospective cohort of VLBW neonates who received ≤ 3 days versus > 5 days of initial antibiotics. Results A total of 121 patients were analyzed of which 117 (97%) were started on antibiotics empirically on admission, and 71 (59%) received ≤ 3 days and 50 (41%) received > 5 days of antibiotics. One (0.8%) infant had a positive blood culture (S. oralis). Demographics [gestational age (p