In continuation of previous work designed to obtain derivatives of 2-mercapto-1,3,4-oxadiazole of possible biological interest, the Mannich bases (III - XXX) were prepared. The compounds prepared bear at position 5, with respect to the oxadiazole nucleus, 3,4,5-trimethoxy and 3,4-dihydroxymethylenephenyl radicals which have proved of interest in other series of derivatives. The antimycotic activity of the compounds is reported.