During a five years period 8 newborns on 2035 admissions developed septic arthritis representing a very low incidence of 4%. Umbilical catheters were used in 3 patients. Staphylococcus aureus was the most frequent etiologic agent and in 6/8 cases blood cultures were positive for the same pathogen agent. Because of the paucity of clinical signs in the first period in the sick neonate, detection of the disorder by the radiologist assumes great importance in the neonatal intensive care unit, as early recognition and therapy may prevent residual deformity.