In this paper, a novel compact dual-band complementary split ring resonator (CSRR)-loaded microstrip patch antenna placed on ground plane loaded with L-shape slot is proposed for satisfying WLAN and WiMAX applications simultaneously. The proposed antenna consists of a complementary split ring resonator (CSRR) embedded on the patch structure and an L-shape slot on the ground plane. The resonant frequency and effective parameters of the CSRR are also determined. In addition, a design evolution and various parametric analysis of the antenna are carried out in order to study the effects of various parameters and to provide information for designing, modifying, and optimizing such an antenna. The CSRR is exploited to create resonance at 5.775 GHz while the L-shape slot resonates at 3.550GHz for dual-band operation. The -10dB return loss bandwidths of the antenna are 290 MHz (3.40-3.69) GHz and 210MHz (5.65-5.86) GHz, which cover both the WiMAX frequency band (3.4-3.69) GHz and the WLAN frequency band (5.725-5.825) GHz. The overall size of the antenna is 37mm×25mm×1.6mm. Gains of 0.5dB and 2 dB are obtained at 3.550 GHz and 5.775 GHz, respectively.