The effects of granulocyte colony-stimulating factor (G-CSF) and interferon-gamma (IFN-gamma) on the oxidative burst of neutrophils (PMNL) in response to blastoconidia and pseudohyphae of Candida albicans were assessed and compared with those in response to N-FMLP. G-CSF enhanced oxidative burst, as measured by superoxide production, in response to both FMLP and opsonized blastoconidia. The enhancement of oxidative burst in response to FMLP was significantly greater (P = .004) than that in response to blastoconidia (65% and 39%, respectively). G-CSF also enhanced oxidative burst in response to pseudohyphae. IFN-gamma enhanced oxidative burst in response to FMLP and opsonized blastoconidia by 53% and 50%, respectively. Moreover, IFN-gamma significantly enhanced oxidative burst in response to opsonized and nonopsonized hyphae by 86% and 65%, respectively. These results demonstrate that G-CSF and IFN-gamma enhance the oxidative burst of PMNL in response to both blastoconidia and pseudohyphae of C. albicans and suggest an immunomodulatory role of the two cytokines in the host defenses against this fungus.