Objective: To determine the relationship between sleep disturbances and fatigue in women with fibromyalgia (FM) and those with chronic fatigue syndrome (CFS) and to assess whether any differences existed between the two groups.

Design: Descriptive comparative.

Setting: Community program on chronic fatigue syndrome and related disorders.

Participants: Sixty-three women who attended the program; 13 had CFS. and 50 had FM.

Main outcome measures: A moderately strong relationship between fatigue and sleepiness was found (r = .63, p .01). Trouble staying asleep was the highest rated sleep disturbance, and fatigue was the most common subjective feeling reported. Women with CFS reported significantly more trouble staying asleep than women with FM. t(61) = 1.81.p < .03.

Conclusions: Data from this study support that women with FM and CFS encounter problems sleeping. Clinicians are encouraged to assess women with FM and CFS for their quality of sleep rather than amount of sleep. Researchers are encouraged to continue study of sleep disturbances in women with FM and CFS to improve understanding of the disturbances and to test the effectiveness of sleep interventions.