AbstractThe fungistatic activity againstPenicillium digitatumandDiplodia natalensisdecreased slightly in ascending a homologous series of alkyl esters of benzimidazol‐2‐ylcarbamic acid from the methyl ester (carbendazim) to the pentyl ester; the hexyl and octyl esters were inactive. 2‐(Acylamino)benzimidazoles were slightly less active than the analogous alkyl benzimidazol‐2‐ylcarbamates. Introduction of a methylene bridge between the benzimidazole ring and the 2‐methoxycarbonylamino group abolished antifungal activity. Methylation of either the carbamate nitrogen or an imidazole nitrogen of carbendazim produced inactive compounds. Replacement of the benzimidazole ring of carbendazim with various other ring systems was accompanied by marked reduction in antifung