During a period of three years in Göteborg, Sweden, 126 cases of giant cell arteritis (GCA) were diagnosed. Histologic evidence of arteritis was found on temporal artery biopsy in 74 (59%). The total annual incidence of GCA was calculated to be 9.3 per 100,000 inhabitants. In the age group over 50, incidence was 28.6 per 100,000. For histologically proven GCA, the incidence was 5.5 per 100,000 of the total population. The corresponding figure in the age group over 50 was 16.8 per 100,000. Twenty-six patients (21%) had a clinical presentation of temporal arteritis, and 23 (18%) had a combined picture of temporal arteritis and polymyalgia rheumatica (PMR). Sixty-seven (53%) had the PMR syndrome without any temporal symptoms, and 10 patients (8%) had a "silent" presentation with only general symptoms. The PMR syndrome was more common among women with GCA (79%) than among men (56%). The group of patients without muscular symptoms contained an equal number of men and women. Eye complications were seen in 15 patients (12%). In 6, the ocular symptoms were transient, while 9 suffered from permanent loss of vision. In 3 of these patients, temporal artery biopsy revealed no evidence of arteritis, and 5 had no clinical signs of localized temporal arteritis.