A report is given on the mycological examination of urine from 146 urological patients. The possible influence of a mixed infection with bacteria on the growth of blastomyces is discussed. Whereas in the organism bacteria and blastomyces can exist well in conjunction, especially gram-negative bacteria in a culture medium can inhibit the growth of blastomyces. The result would be wrongly negative culture results. In our tests mixed infections of candida albicans and/or candida guilliermondii with escherichia coli and/or enterococci were found. Therefore it is recommended to add a suitable antibacterial antibiotic to the test material and to carry out a simultaneous bacterial urine culture. Where there is a urological primary disease and the urine has to be sent a long way we recommend Gentamycin, in a dosage of 200 micrograms/ml urine, for its good sensitivity.