The authors studied the potential for suicidal behaviour in patients with chronic fatigue syndrome. 269 patients with chronic fatigue were evaluated. Of the 86 patients who met criteria for chronic fatigue syndrome, 13 reported attempting suicide at least once, compared to 3 of 86 age & sex matched fatigued controls from the same sample. It is concluded that patients with chronic fatigue syndrome have an increased risk of lifetime suicide attempts when compared to patients with chronic fatigue.