We evaluated the courses of 115 consecutive cases of pediatric acute leukemia treated with induction chemotherapy. Seventy-two patients developed fever associated with neutropenia; 15 developed systemic fungal infections. We reviewed multiple demographic and treatment characteristics of these patients in an attempt to identify potential risk factors for the development of invasive fungal disease (IFD). Risk factors identified in a univariate analysis included duration of neutropenia after first fever (P less than .0001), diagnosis of acute nonlymphocytic leukemia (ANLL) (P = .003), onset of fever and neutropenia within 5 days of starting induction chemotherapy (P = .009), and multiple (greater than one) surveillance culture sites positive for fungal organisms (P = .02). In a multiple logistic regression analysis, duration of neutropenia (P less than .001) remained a significant risk factor. The study group of patients had a significantly higher risk of fungal infections than a matched group of leukemia patients developing fever with neutropenia due to postremission consolidation chemotherapy (P = .003). In the first 48 patients, 14 (29%) developed IFD. In the subsequent patients (n = 24), intravenous miconazole (5 mg/kg every 8 hours) was begun at the time of the first fever. One of the 24 patients (4%) given miconazole developed IFD. The use of miconazole was a negative risk factor for the development of IFD in univariate (P = .01) and multivariate (P = .05) analysis. We conclude that pediatric leukemia patients who develop fever associated with neutropenia during induction chemotherapy are at high risk for developing IFD. The role of intravenous miconazole at the time of the first fever in this group deserves further study.