We sought to describe the common causes of infection in patients presenting to the Emergency Department (ED) with elevated temperature and chemotherapy-induced neutropenia and to determine the frequency with which the ED diagnosis of infection is consistent with the final hospital discharge diagnosis. We performed a structured restrospective chart review of ED patients with fever (T > 38 degrees C) and neutropenia (absolute neutrophil count < 1000/mm(3)) over a 2-year period. Fifty-five episodes of neutropenic fever occurred in 52 patients (mean age 52 years, range 18-86 years; 53% men). Twenty-six patients (47%) were found to have a specific infection identified. Of these, 21/26 (81%; 95% CI, 70-91%) had the source of infection identified while in the ED. All patients who had a focal site of infection identified during their hospitalization were diagnosed in the ED (100%; 95% CI, 86-100%). The other 5 patients, without a source identified in the ED, were found to have bacteremia. The 29 patients without a source identified in the ED were hospitalized and had negative blood and urine cultures and were discharged to home after resolution of fever. A thorough history, physical examination, chest radiograph and urinalysis in the ED identified all patients with a focus of infection. Meticulous ED evaluation of patients with neutropenia and fever may be sufficient to diagnose most sources of infection; however, a significant number of patients without an identifiable focus may have bacteremia.