A retrospective chart review describing the rates of occurrence, methods of evaluation, and diagnoses of patients complaining of fatigue in a university family medicine teaching practice was performed. After excluding patients in whom an unequivocal explanation for the fatigue was reached at the initial encounter, 118 patients aged 15 years and over were identified during a two-year study in a practice with about 6,000 active adult patients (9.9/1,000 patients per year). The age and sex distributions of the cases were identical to those of the active patient population. The average laboratory examination cost approximately $48. An average of 2.7 laboratory tests per patient were ordered. Although 12 percent of laboratory tests were abnormal, laboratory tests were important in securing a diagnosis in only 9 of the 118 patients. Clinical diagnoses were classified as either primarily biomedical or primarily psychosocial. Psychosocial diagnoses were identified in 50 percent of patients, while primarily biomedical diagnoses were found in 22 percent. No diagnosis was made in 28 percent of patients. Sixty-eight percent of patients had at least one follow-up visit. Failure to follow up was uncommon in patients with depression or biomedical diagnoses other than viral syndromes but was common with other primarily psychosocial diagnoses.