In an open prospective study, 40 women with severe recurrent vulvovaginal candidiasis were treated with ketoconazole 400 mg daily for two weeks, followed by prophylactic ketoconazole 400 mg daily for five days with onset of menses for three menstrual cycles. Initially, 100% of the women responded clinically, however, 24.3% developed recurrence of symptomatic candidal vaginitis during the period of cyclical prophylaxis. By the end of six months observation, 56.8% of the patients' symptoms had recurred; however, symptomatic recurrence during the next six months was uncommon. The clinical attack rate of symptomatic episodes was significantly reduced during the one-year observation. One patient developed reversible mild hepatitis on therapy. No evidence emerged that topical genital therapy of male partners was beneficial in reducing vaginal candida recolonization. Maintenance prophylactic therapy with oral ketoconazole appears effective in preventing recurrent episodes of vulvovaginal candidiasis.