Photoresist monomers of following Formula 1, photoresist polymers thereof, and photoresist compositions using the same. The photoresist composition has excellent etching resistance, heat resistance and adhesiveness, and is developable in aqueous tetramethylammonium hydroxide (TMAH) solution. In addition, the photoresist composition has low light absorbance at the wavelength of 193 nm, 157 nm and 13 nm, and thus is suitable for a photolithography process using ultraviolet light sources such as VUV (157 nm) and EUV (13 nm) in fabricating a minute circuit for a high integration semiconductor device. wherein, R1, R2, R3, Y, W, m and n are as defined in the specification.