Methylene blue (MB) alone, MB metabolites in the urine and the effect of MB plus alkalization on Candida species were determined. MB was used for the treatment of childhood renal candidiasis (CRC) in 3 patients as an irrigating solution. Besides irrigation, fluconazole 3 mg/kg/day intravenously and MB 0.2 mg/kg/day were administered perorally. Urine cultures were cleared of Candida. DMSA scans obtained after 6 months showed no evidence of scarring. MB can be used for irrigation of the urinary tract, with fewer side effects than amphotericin B (AB). Additionally we advocate the use of ureteral catheters instead of nephrostomy in the treatment of CRC.