The significance of indirect immunofluorescence using Candida albicans germ tube as well as blastospore antigens in the diagnosis of isolated candiduria in non-neutropenic, critically-ill surgical patients was assessed. Ten patients with isolated candiduria, 12 with systemic candidosis and 10 with multifocal muco-cutaneous candidosis were included in the study. The sera of another 10 critically-ill patients with no signs of candidosis served as controls. The patients' sera were tested for IgG, IgA and IgM antibodies. The results obtained confirmed that indirect germ tube immunofluorescence is a useful procedure for differentiating systemic candidosis from colonisation of the urinary tract. Indirect immunofluorescence with blastospores, although more sensitive than germ tube immunofluorescence, cannot distinguish muco-cutaneous candidosis from systemic candidosis. Therefore, indirect germ tube immunofluorescence is regarded a useful complementary test to evaluate candiduria in non-neutropenic, HIV-negative, critically ill patients.