Provided are biocidal compositions comprising 2,6-dimethyl-m-dioxane-4-ol acetate and a non-formaldehyde releasing biocidal compound selected from the group consisting of: a brominated nitroalkanol, a 2-halo-2-(halomethyl)glutaronitrile, and 2-phenoxyethanol. The compositions are useful for controlling microorganisms in aqueous or water containing systems.
