Recently, the demand for wireless devices that support multi-band frequency has increased. In fact, employing single-band antennas leads to large space requirement in handheld devices. Therefore, due to the space constraints in mobile devices, an antenna which will cover multiple bands of frequencies will be the best solution in order to allow more space in the mobile devices. The integration of such technology in mobile communication system has led to a great demand in developing small size antenna with multi-band operation that is able to operate in the required system. In this paper, a triple band planar inverted-F antenna (PIFA) is proposed. The antenna has been measured and found to operate at three operating frequencies of GSM bands (900 MHz and 1800 MHz), and Bluetooth band (2400 MHz). A dual L-shaped slot was used on the patch to obtain the triple-band resonant frequencies. Performance of the antenna has examined and results have shown that the proposed antenna can successfully cover frequencies 900 MHz, 1800 MHz and 2400 MHz.