Provided are compositions comprising 2,6-dimethyl-m-dioxane-4-ol acetate and a biocidal compound selected from the group consisting of: a biocidal oxazolidine 1-(3-chloroallyl)-3,5,7-triaza-1-azoniaadamantane and tris(hydroxymethyl)-nitromethane. The compositions are useful for controlling microorganisms in aqueous or water containing systems.
