Introduction: Early neonatal sepsis is a public health problem and the leading cause of complications and deaths in neonatal intensive care units. Objective: To associate obstetric and neonatal risk factors with the presence of early sepsis in Cartagena (2014-2015). Material and Methods: Case Study and Retrospective Controls. The sample is composed of 183 cases and 366 controls, including patients who simultaneously meet inclusion and exclusion criteria. A bivariate analysis was performed and a logistic regression multivariate model was constructed . Results: Among the variables associated with early sepsis in which the risk could be defined, the following may be listed: premature rupture of membrane > 18 hours (OR 12.78 CI 95% 4.01-36.6), risk of sepsis due to vaginal childbirth (OR 2.69 95% CI 1.58-4.57), male newborn (OR 2.38 95% CI 1.38-4.08), and prematurity (OR 3.13 IC 95% 1.24-7.86). Conclusions: In mothers with premature rupture of membranes and vaginally born premature infants, a causal association with cases of early neonatal sepsis is evident. Keywords : Newborn, risk factors, sepsis, vertical transmission of infectious disease.