Thirty-three primary fibromyalgia patients were investigated for chronic fatigue syndrome symptoms. Significant fatigue was reported by 21/33 patients (63.6%), and patients reported various flulike symptoms, yet only 7/33 patients (21.2%) fulfilled criteria for the chronic fatigue syndrome. Only one patient reported painful lymph glands and four patients reported fever. Thus, symptoms of painful glands or fever might serve as clinical indicators, distinguishing between fibromyalgia and the chronic fatigue syndrome.