Twenty-two patients with fibrositis, selected from a general medical outpatient population by a screening questionnaire and subsequent evaluation, were compared with age-, sex-, and clinic-matched patients without fibrositis. Although there was a high prevalence of musculoskeletal complaints in both groups, the fibrositis patients had a uniform constellation of symptoms, including axial pain, severe aching and stiffness, morning fatigue, and modulation by specific factors. They also had a higher incidence of tension headache and irritable bowel syndrome. The use of a dolorimeter demonstrated that fibrositis patients had many more areas of localized tenderness than control patients, but also that fibrositis patients did not have diffusely diminished pain threshold and tolerance. Using the criteria of this study, fibrositis appears to be a common and readily definable syndrome within the spectrum of soft tissue rheumatism.