A new quad-band planar monopole antenna is presented. The proposed antenna consists of a wide-band planar monopole antenna and the triple band-notched slots. In order to generate quad-band characteristic, we insert three kinds of slots in the interior of the radiating element, such as connected three U-shaped slots, unconnected triple Pi-shaped slots and combination of double Pi-shaped slots and (sic)-shaped slot. This new approach is suitable for creating wide-band antenna with narrow-band interferer rejection.