Fluconazole-sensitive (SC 5314) and -resistant (clinical isolate 1173) Candida albicans strains were compared in terms of their osmotolerance and tolerance to toxic sodium cations. The two strains did not differ in their tolerance to high osmotic pressure in general but exhibited distinct sensitivities to sodium cations. Although the fluconazole-resistant 1173 strain contained, under all conditions tested, significantly lower intracellular amounts of Na+, it was much more sodium sensitive than the SC 5314 strain. The addition of subinhibitory concentrations of fluconazole to media supplemented with NaCl significantly influenced the growth of both strains and resulted in substantially elevated intracellular sodium concentrations compared with growth in medium containing NaCl but no fluconazole.