A herbicidal composition comprising a herbicidal amount of a mixture of(a) at least one S-.alpha.,.alpha.-dimethylbenzyl-N-alkylenimine carbothiolate of the formula ##STR1## wherein R represents a lower alkyl group, m is 0, 1 or 2, n is 4, 5 or 6, and the chain of n --CH.sub.2 -- linkages may contain one oxygen atom, and(b) at least one compound selected from the group consisting of N-[p-(p-chlorobenzyloxy)phenyl]-3,4,5,6-tetrahydrophthalimide, 1,3-dimethyl-4-(2,4-dichlorobenzoyl)-5-(p-tolylsulfonyloxy)pyrazole, 3,4-dichloropropionanilide, and 1-(2-phenylpropyl)-3-(4-tolyl)urea, and a method for controlling weeds, which comprises applying 1 to 2,000 g/10 ares of the aforesaid composition to the locus where the weeds are growing or will grow. The composition is especially useful in rice cultivation for controlling weeds of Family Gramineae (e.g., barnyard grass) and broad-leaved weeds without toxocity to rice.