The authors consider the presence of streptococcus of group B in the vaginal flora of the medical and paramedical staff who work at the Obstetrical and Gynaecological Clinic and at the Department of Neonatology at the S. Matteo Polyclinic. The identification of fellows (6 cases, 6.8%) colonized by GBS improves the hypothesis of the possibility of a hospital-transmission of the microorganism , and this transmission explains the possible bacterial colonization of newborns, whose mothers are GBS negative. The importance of such a type of transmission has to be referred overall to the possible onset of a neonatal meningitis, in regard to its mortality (20-30%) and to the neurological complications, which can be observed in the child even later on.