The present invention is directed to a method for treating a surface of a filled microporous membrane. The microporous membrane includes a polyolefinic matrix, inorganic filler distributed throughout the matrix, and a network of interconnecting pores throughout the membrane. The method includes sequentially (1) contacting the membrane with a first treatment composition comprising an epoxy-silane which is in intimate contact with the inorganic filler; (2) subjecting the membrane of (1) to conditions sufficient to effect a first reaction between the inorganic filler and the silane groups of the epoxy-silane compound; (3) contacting the membrane of (2) with a second treatment composition comprising polyalkylene polyamine, an amine functional polysaccharide and/or an amino silane; and (4) subjecting the membrane of (3) to conditions sufficient to effect a second reaction. Treated membranes also are provided.