The objectives of this study were: (i) to compare the sleep quality at home of patients with fibromyalgia with that of healthy controls; and (ii) to examine the factors associated with sleep quality in patients with fibromyalgia. In addition to anthropometric measures, 75 women with fibromyalgia and 48 healthy controls completed standardized questionnaires that assessed sleep quality, functional impairment (Fibromyalgia Impact Questionnaire), depression, anxiety and physical activity level. Comparisons between groups, correlation coefficients and a series of hierarchical multiple regressions were performed. The global Pittsburgh Sleep Quality Index scores were worse in patients with fibromyalgia than in the controls. This result was partly explained by the Fibromyalgia Impact Questionnaire score. For the patients with fibromyalgia, the results of the first model that tested the importance of demographic factors were not statistically significant. In the disease-related model, the duration of symptoms and symptom severity contributed to poor sleep quality. A measurement of physical activity participation and the sum of the skinfold thickness were added to the demographic factors. In the psychological model, the level of anxiety contributed to poor sleep quality. When all variables were entered simultaneously, the level of physical activity, duration of symptoms and symptom severity remained significant determinants of sleep quality. In conclusion, our results showed that the symptoms associated with fibromyalgia contributed to poor overall sleep quality in patients compared with healthy subjects. The findings also suggest that the duration of symptoms, symptom severity and especially a sedentary lifestyle contributed to decreased sleep quality in patients with fibromyalgia.