The candidacidal activity of neutrophils from BALB/c, C.B-17 +/+, C.B-17 scid/scid, scid/scid-bg/bg, C57BL/6 bg/+, C57BL/6 bg/bg, NIH III bg/bg-nu/+, and bg/bg-nu/nu mice was assessed. Killing of blastoconidia was moderately deficient with neutrophils from 2 strains of homozygous beige mice; however, neutrophils from all homozygous beige strains had a significantly decreased capacity to kill Candida albicans hyphae. This is the first demonstration of a decreased capacity of beige mouse neutrophils to kill C. albicans hyphae. The latter defect could be related to the enhanced susceptibility of beige mice to candidiasis.