Fatigue is one of the 10 most common reasons for visiting a physician. Yet little is known about its course or impact, from the patient's perspective, on quality of life or utilization of medical care. The Dartmouth COOP Project, a primary care research network, conducted a one-year prospective study comparing chief complaint fatigue (CCF) patients with two age/sex matched comparison groups (N = 243). Results show that almost 67% of the CCF patients improved over one year; however, they had much higher utilization rates and substantial limitations in physical and emotional function. Fatigue was associated with physical symptoms and interference with many aspects of daily life. We conclude that fatigue has a powerful, adverse effect on quality of life. We hope the findings may help physicians to better understand and treat patients who seek care for fatigue.