One hundred adults diagnosed with multiple chemical sensitivity (MCS), were studied to determine the prevalence and overlap of Chronic Fatigue Syndrome (CFS) and Fibromyalgia Syndrome (FMS). The patients were evaluated for CFS and FMS using diagnostic tactics from the US Center for Disease Control (1994) and the American Collage of Rheumatology (1990). Data was recorded regarding the number of CFS and FMS pressure points which demonstrated pain upon manual palpation. The results of the study suggest that MCS rarely occurs alone, as almost all of the 100 patients studied met the criteria for CFS, and about half also had FMS. FMS was twice as prevalent in women as men.