A new culture medium (DTM) has been devised for the simplified diagnosis of dermatophytosis. Results can be evaluated by a color change in the medium without detailed knowledge of colony morphology. Although microscopic features are required for positive botanical identification, the nonmycologist can now recognize a griseofulvin-sensitive infection quite well by noting the change of the color of the agar from yellow to red. The medium is superior to currently available commercial preparations in eliminating bacterial contamination, reducing fungal contaminants, and allowing a higher recovery rate of dermatophytic fungi and Candida albicans.