The present invention relates to a light-guiding cover and an illumination device having the same. The light-guiding cover, for guiding light beams emitted by at least one light-emitting diode (LED), has a light-guiding portion and a light output portion. The light-guiding portion has a light input surface for transmitting light beams thereto and a connecting surface. The light output portion formed on one end of the light-guiding portion has an optical surface adjoining the connecting surface. The light-guiding cover is substantially symmetrical and defines a central axis. The light beams received by the light-guiding portion are guided by the light input surface for light reflection from one side to another side of the optical surface across the central axis to exit from the light-output portion. Thus, the illumination device having the light-guiding cover can illuminate in an omni-directional manner.