A mesh screen of polyester filaments for screen printing is subjected to a treatment with low temperature plasma in an atmosphere of a non-oxidizing inorganic gas to such an extent that a crosslinked layer having a thickness of 0.001 to 0.1 .mu.m is formed on the surface of the polyester filaments and the surface of the filaments is provided with protrusions and concavities having a diameter of 0.01 to 0.1 .mu.m in a distribution density of 1000 to 6000 per .mu.m.sup.2 of the surface area of the filament. The thus treated mesh screen is advantageously improved, with no adverse influences on the mechanical strength, in respect of the adhesion between the filament surface and a photosensitive resin composition applied to the mesh screen for photolithographic patterning. The plasmatreated mesh screen is also advantageous in respect of the decreased resistance against transfer of a printing ink through open meshes.