A series of S-acylderivatives of N-ethylthiosalicylamide (substances I leads to XXIII) was prepared and tested for in vitro antifungal activity. The substances, not previously reported, were prepared by the reaction of 2-mercapto-N-ethylbenzamide with suitable acylating agents. The fungistatic activity of the prepared products was tested in vitro against Candida albicans and Trichophyton mentagrophytes. The results given in Table I show that the S-acylderivatives of N-ethylthiosalicylamides have interesting antifungal activity. From examination of the results (Tables I and II) some information on the structure-activity relationship was obtained. 2-Acetylmercapto-N-ethylbenzamide (I) and 2-propionylmercapto-N-ethylbenzamide (III) proved the most active of the compounds tested.