A multiband monopole antenna with modified fractal loop parasitic is presented. Especially, bow-tie stubs and a modified fractal loop are attached to the sides and bottom of a strip line monopole antenna, respectively, in order to generate the multi-resonant frequencies for the applications of wireless communication systems. The characteristics of the presented antenna have been examined by using the simulation software. The comparison between the simulated and measured results confirms the good agreement. The results show good multiband operation with 10dB impedance bandwidths of 15.55%, 8.75%, and 31.94% at the resonant frequencies of 1.8GHz, 2.4GHz, and 3.6GHz, respectively, which cover the operating band applications of DCS 1800, WLAN (IEEE802.11 b/g), WiMAX, and IMT advanced system (4G mobile communication system).