ObjectivesLate initiation of breast feeding (LIBF) is associated with increased neonatal mortality and morbidity. This study aimed to assess the association between intrapartum, early postpartum and neonatal factors, and LIBF in Bangladesh.Design, setting and participantsIn this analysis, we used data from the mothers participating in a cluster-randomised controlled trial (Rang-Din Nutrition Study) conducted in rural northwest Bangladesh. Mothers (n=3594) were interviewed about the time of initiation of breast feeding, and peripartum maternal and neonatal complications within the first 72 hours of delivery. LIBF was defined as initiation of breast feeding 1 hour after birth. Factors associated with LIBF were identified by multivariable logistic regression analysis.Main outcome measuresPrevalence and associated factors of LIBF.ResultsThe prevalence of LIBF was 18.5%. Factors significantly associated with LIBF in multivariable logistic regression were assisted vaginal delivery (adjusted OR (AOR) 2.17, 95% CI 1.44 to 3.27); delivery by caesarean section (AOR 9.67, 95% CI 7.21 to 12.96); maternal health problems during childbirth (AOR 1.61, 95% CI 1.30 to 2.00); preterm newborns (AOR 1.39, 95% CI 1.09 to 1.78); newborns moved slowly immediately after birth (AOR 1.43, 95% CI 1.05 to 1.94); and sick newborns (AOR 1.60, 95% CI 1.12 to 2.29).ConclusionsFindings from this study suggest that to reduce LIBF, peripartum maternal and neonatal complications should be prevented and treated.Trial registration numberNCT01715038.