We sought to identify risk factors associated with the time to febrile neutropenia in patients with intermediate-grade, non-Hodgkin's lymphoma (NHL) who were receiving treatment with CHOP chemotherapy. Data were collected from 12 community and academic oncology practices participating in the Oncology Practice Pattern Study between 1991 and 1999. We reviewed the medical records of 577 intermediate-grade NHL patients who received initial CHOP chemotherapy and evaluated risk factors associated with time to first febrile neutropenic event. A febrile neutropenic event was defined as a body temperature of > 100.6 degrees F and an ANC nadir < 1000/mm3. A total of 160 patients experienced 224 febrile neutropenic events. The risk of febrile neutropenia was significantly associated with age > or = 65 years (p = 0.001), cardiovascular disease (p = 0.020), renal disease (p = 0.006), baseline hemoglobin < 12 g/dl (p = 0.018), > 80% planned average relative dose intensity (ARDI; p = 0.018), and no prophylactic colony-stimulating factor (CSF) use (p = 0.046). First febrile neutropenic events occurred by day 14 of cycle 1 in one-half of patients experiencing febrile neutropenia. In multivariate analysis, the risk of febrile neutropenia remained significantly associated with age > or = 65 years (HR = 1.65, 95% CI: 1.18-2.32), renal disease (HR = 1.91. 95% CI: 1.10-3.30), cardiovascular disease (HR = 1.54, 95% CI: 1.02-2.33), baseline hemoglobin < 12 g/dl (HR = 1.44, 95% CI: 1.04-2.00), > 80% planned CHOP ARDI (HR = 2.41, 95% CI: 1.30-4.47), and no CSF prophylaxis (HR = 2.13, 95% CI: 1.20-3.76). Such a model may permit the identification of patients at greatest risk of febrile neutropenia and, therefore, candidates for the selective prophylactic use of the hematopoietic growth factors.