The aim of the present study was to investigate the prevalence of fibromyalgia and allied symptoms in patients with psoriasis. During a 3-year period from 1997 until 2000, 1269 patients were consecutively diagnosed with psoriasis. All patients were questioned about musculoskeletal symptoms and those with such symptoms were further examined according to a standardized protocol. In total 335 of 1269 patients had musculoskeletal symptoms. More women than men had such complaints, 33% versus 18.5%, respectively. As many as 13% of the women fulfilled the American College of Rheumatology 1990 (ACR-90) criteria for fibromyalgia, while 14.1% had symptoms compatible with chronic widespread pain without meeting the fibromyalgia criteria. In total, 8.3% suffered from fibromyalgia and 9% from chronic widespread pain. The results indicate that fibromyalgia and allied symptoms are frequent in female patients with psoriasis and constitute important problems with regard to disability and health-related quality of life. Only 35 of 105 patients with fibromyalgia had previously been diagnosed with psoriasis and the diagnostic label of fibromyalgia was new to 51 of them. Female patients with symptoms of psoriasis and pain seem to constitute a subgroup which deserves further studies.