Bloodstream infection (BSI) is one of the main causes of sepsis and death in newborns. The relative importance of nosocomial and non-nosocomial agents in developing countries is not clear. We conducted a prospective study of newborns hospitalized with a first episode of BSI in order to classify it as early, late or nosocomial, describe the clinical and microbiological charateristics, and explore risk factors between hospital-acquired vs commu-nity-acquiered BSI (HA-BSI vs CA-BSI). Twenty-seven newborns with a first episode of BSI were identified. Streptococcus agalactiae and coagulase negative Staphylococcus were the main agents in CA-BSI and HA-BSI, respectively. The only significant intrinsic risk factor between HA-BSI and CA-BSI was gestational age. The frequent finding of S. agalactiae warrants routine screening and prophylaxis in pregnant women. The risk factors for HA-BSI were mostly extrinsic, and thus, susceptible of being modified.