Fibromyalgia syndrome (FMS) is characterized by widespread musculoskeletal pain, multiple tender points, and fatigue, and affects 3-6 million Americans, 75% of whom are female. The purpose of the present study was to examine the illness perceptions of women with FMS using Leventhal's common sense self-regulation model. Ninety-one women with FMS took part in this study. Pearson correlations and stepwise multiple regressions were used to assess relationships among variables and explanation of variance in the outcomes of health behaviors, FMS impact, and subjective physical and mental health. Participants viewed their FMS as chronic with a somewhat fluctuating course, having serious consequences in their lives, and difficult to understand in a coherent fashion. The women tended to find their FMS emotionally distressing and unamenable to personal control or efficacious treatment. Emotional representations explained 41% of the variance in mental health scores and 17% in reported health behaviors. Overall, this sample of women with FMS had fairly negative perceptions of their illness. As suggested by Leventhal's model, cognitive and emotional representations predicted different outcomes. Interventions that address psychological as well as the physical components of the illness experience may offer benefits for women with FMS.