The present invention discloses a microbicidal compositions including (a) cyanodithiocarbimate and (b) an N-alkyl heterocyclic compound; a triazole compound or salt thereof or metal complex thereof; a microbicide with an activated halogen atom or a formaldehyde releasing compound; 1,4-bis(bromoacetoxy)-2-butene; 2-(thiocyanomethylthio)benzothiazole; a methylene-bis(thiocyanate); a halogenated acetophenone; a halopropynl compound; an iodosulfone; a phenol; a halocyanoacetamide compound and/or a quaternary ammonium compound are described. Components (a) and (b) can be present in a synergistically effective amount to control the growth of at least one microorganism. Methods for controlling the growth of microorganisms with the compositions are also disclosed.