In a prospective study, the age- and gender-specific incidence and features of clavicular fractures were studied during 1989 and 1990. The population at risk consisted of about 200,000 individuals aged 15 or above in the county of Uppsala, Sweden. There were 187 clavicular fractures in 185 patients corresponding to an annual incidence of 50/100,000 (males 71/100,000, women 30/100,000). Males were significantly younger and sustained comminuted fractures more often than women. The fracture incidence decreased with age in both genders, although the reduction was significant only in men. Bicycle accidents most frequently caused clavicular fractures in both genders, whereas sports activities were significantly more common in men. Right and left clavicles were almost as frequently fractured, and a direct fall on the shoulder was the most frequent mechanism of injury for both genders. There was no difference between genders in the anatomical location with about three of four fractures occurring through the middle part and one of four through the acromial part of the clavicle. Ninety-five percent healed uneventfully, while non-union developed in 5% - evenly distributed between the middle part of the clavicle and the acromial part.