The present invention provides polymer microcapsules of biocide, useful for preparing coating materials such as interior and exterior paints, which comprises of an active agent biocide and an encapsulating polymer. Microcapsules described in this invention are prepared by dispersing an organic phase containing an active agent either in dissolved state or dispersed state in a polymer solution using a low boiling point solvent, in an aqueous phase containing an emulsifying agent; agitating the emulsion at 800-1200 resolution per minute for 3-5 hours at 25 -27° C. to evaporate the low boiling point solvent and thus to permit the formation of the microcapsules; separating the microcapsules, washing with water and drying the microcapsules at temperature between 25-35° C.