Disclosed is a method for forming salicide in a semiconductor device. The method comprises the steps of: forming a first and a second gate oxide film and in a non-salicide region and a salicide region, the first gate oxide film being thicker than the second gate oxide film; forming a conductive layer and a nitride based hard mask layer, and then selectively removing the conductive layer, the hard mask layer, the first gate oxide film, and the second gate oxide film, thereby forming gate electrodes and simultaneously exposing an active region of the salicide region; forming a spacer oxide film on an upper surface, except for the hard mask layer, of a second resultant structure; selectively removing the spacer oxide film, thereby forming a spacer and simultaneously exposing the active region of the salicide region; removing the hard mask layer; and forming a salicide film on the upper surfaces of the gate electrodes and on the surface of the active region in the salicide region. Therefore, a non-salicide region and a salicide region can be formed selectively and simultaneously in a one-chip semiconductor device, so that the number of steps for a salicide forming process can be reduced.