Group B Streptococcus (GBS) causes maternal infections during perinatal period and serious neonatal infections. Their frequency in our country is still unknown. This study analyzed the clinical and epidemiological characteristics of 13 neonates inborn at the Instituto Nacional de Perinatología with early or late onset group B streptococcal infection. The incidence of early onset diseases (EOGBS) was 0.7 cases/1,000 live births among 20,054 inborn, and 1 case/20,000 live births of late onset diseases. EOGBS was more common in preterm newborn (median 33.2 w), low birth weight (median 2.025 g) with several maternal risk factors. Lethality rate was 38.5% (5/13). GBS is a recent important pathogen in our institute that must be investigated in another institution of our country. Group B Streptococcus; neonatal septicemia; neonatal pneumonia.