The optimal management of fever in granulocytopenic cancer patients remains controversial. Antibiotic monotherapy is increasingly an option for the initial empiric treatment of febrile granulocytopenic patients with solid tumors. Available data show that response to empiric therapy is often more related to disease classification (solid tumors vs. acute leukemia) than to the regimen used. In this study we based empiric monotherapy on the underlying disease (solid tumors) in treating 33 episodes of fever in 26 granulocytopenic children with cancer. We investigated the potential effectiveness of single daily doses of ceftriaxone administered empirically in febrile granulocytopenic children with solid tumors. Fever was treated successfully with ceftriaxone monotherapy in 91% (30/33) of febrile episodes. None of the patients died as a result of primary infection. These results suggest that empirical monotherapy with once-daily ceftriaxone is safe and effective. In addition, when compared with other extended-spectrum cephalosporins such as ceftazidime, once-daily administration of ceftriaxone reduces cost and patient inconvenience, allowing convenient parenteral therapy even on an outpatient basis.