This paper presents the design of a compact triple band-notched ultra-wideband (UWB) two element multiple-input multiple-output (MIMO) antenna. To validate the simulation results, the prototype of the design is fabricated and experimentally measured. From the experimental results, it is observed that the proposed design, operating in the frequency range 2.5-12 GHz, successfully rejects three interfering bands, i.e., the WiMAX band, WLAN band, and X-band satellite communication downlink channel, when a triple bandgap CSRR-loaded EBG structure is embedded close to the feedline of the UWB antenna. In the ground plane of the MIMO antenna, a rectangular slot and a mirrored pair of F-shaped stubs are added to minimize the mutual coupling between the UWB elements. The proposed MIMO antenna has good wideband isolation between the elements (> 20 dB), high diversity gain (10 dB), and low envelope correlation coefficient (< 0.02) over the entire UWB.