Twelve women with vaginal Candida krusei infection were evaluated. In vitro antifungal susceptibility testing and molecular typing were performed. Patients infected with C. krusei frequently had refractory vulvovaginal signs and symptoms that were otherwise indistinguishable from vaginitis due to other yeasts. Patients were 32-63 years old and had previously received multiple courses of antimycotic agents, including fluconazole and miconazole. The most active azole in vitro was clotrimazole, with a 90% minimum inhibitory concentration of 0.25 microg/mL. Four of 6 patients treated with boric acid had clinical and mycological cure. Two dominant genotypes of C. krusei were identified via contour-clamped homogenous electrical field analysis. No major genotypic change was observed in successive isolates from the same patient in most cases, suggesting that these refractory cases were relapses. C. krusei is a rare but important cause of refractory vaginitis and is unique because of its intrinsic resistance to fluconazole.