This paper presents the electrically small U-slot loaded circular microstrip patch antenna with Complementary Split Ring Resonator (CSRR). The technique of U slot loading is used for operating antenna in dual band and CSRR technique to make antenna compact and CSRR for compactness is used. The simple circular patch antenna resonates at 5.71 GHz with return loss of -11.38 dB. The proposed antenna (with U-slot and CSRR) enhanced the matching upto-37.47 dB at the 3.47 GHz and -13.7dB at the frequency 3.98 GHz circular patch antenna and U-slot loaded circular microstrip patch antenna with CSRR are simulated using Ansoft HFSS and verified with the experimental results. General Terms Return Loss, Bandwidth, Antenna Size