The determination of the in vitro activity of antimycotics against dermatophytes has for long been considered as irrelevant from a practical point of view. Recently, however, this approach has been questioned. Various different tests such as agar diffusion test, agar dilution test and broth dilution test can be used for the determination of minimum inhibitory concentrations with dermatophytes. A close correlation between in vitro data and clinical outcome could especially be demonstrated for the micro dilution test. In future, the antimycogram of a dermatophyte isolated from an individual patient should gain more and more importance for the selection of the drug to be used and its dosage.