Miconazole was used as a fungistatic genitourinary irrigant in the management of 10 patients with persistent candiduria. All patients were in the older age group, with a mean age of 77.6 years, and they were debilitated by a variety of medical problems, including major surgery, neoplasia, recurrent bacterial infection, diabetes or other metabolic dysfunction. Miconazole at a concentration of 50 mcg. per ml. was administered continuously during 24 hours for 5 consecutive days via a urethral catheter. Candiduria resolved in 8 of the 10 patients, with 1 requiring a second course of miconazole at a concentration of 100 mcg. per ml. Two patients manifested other foci of infection, necessitating intravenous and intravesical amphotericin B. Stability studies showed that the miconazole irrigation solutions maintain their antifungal activity for 11 days at room temperature. The 5-day cost (drug and materials) of the miconazole irrigation at 50 mcg. per ml. was $17.75 versus $76.75 for an equal course of therapy with amphotericin B. In addition, compared to amphotericin B as an antifungal genitourinary irrigant, miconazole is prepared more easily, requires less labor and preparation time, and does not require refrigeration or protection from light. These clinical observations indicate that miconazole is a cost-effective antifungal genitourinary irrigant.