A tri-frequency CPW-fed monopole antenna is proposed. The antenna is printed on a substrate with a couple of unequal monopoles and asymmetrical ground plane. In addition, a inverted L-shaped stub is added on the ground plane to get third resonant frequency so that antenna offers three resonant frequencies at 1.42 GHz, 1.82 GHz and 2.62 GHz for the commercial wireless applications. The simulated results show that the proposed antenna has 10-dB impedance bandwidths of 370 MHz (1.36-2.73 GHz). Effects of varying the dimensions of the monopoles have been studied. The proposed antenna employs the advantages of the (CPW) feed line to alter the structure of the antenna into a single plane, thereby making easier the integration on the circuit board of communication devices. The simulation result of an antenna has been carried out using Zealand's IE3D which is based on Method of Moments (MoM). © 2015 IEEE.