We evaluated the wide variation in the reported incidence of fractured clavicles (0.2% to 3.5%) in newborns by screening 626 consecutive infants delivered vaginally for fractures. One of us (P.R.J.) evaluated all infants, twice during the initial hospital stay and 2 weeks later. Eighteen fractured clavicles were identified for a frequency of 2.9% (18/626). One fracture was discovered on the first hospital examination, 10 on discharge, and 7 at follow-up. Only 2 patients had symptoms usually associated with fractured clavicles. The most reliable clinical sign for in-hospital diagnosis was difficulty in feeling the margins of the affected clavicle when compared with the normal clavicle. The mean birth weight of the infants was 3604 g (range, 3000 to 4930 g), and no obstetric complications occurred. The reported frequency of fractures diagnosed clinically during hospitalization significantly underestimates their occurrence. Most newborn infants with fractures have no symptoms and minimal physical findings during the first days of life, making repeated examination necessary.