3-(1,3,4-THIADIAZOL-2-YL)-5-ACYLOXY(CARBAMOYLOXY)HYDANTOIN COMPOUNDS OF THE FORMULA: ##STR1## in which R is alkyl, haloalkyl, alkylmercapto or alkylsulfonyl, R.sup.1 is alkyl, and R.sup.2 is alkylcarbonyl, alkoxycarbonyl, alkylcarbamoyl or optionally substituted arylcarbonyl; Are remarkably active as herbicides and are particularly useful as selective herbicides in cotton cultivations or in cereal crops, including corn.