This paper presents a compact design of highly effective reduced mutual coupling of two-element MIMO antenna for mobile terminals. In order to scale down the antenna size and to degrade the mutual coupling between the antenna elements, two complementary split ring resonators (CSRRs) are etched on the ground plane. Miniaturizing of about 60 % in the antenna total area is achieved and about 10 dB improvement in the mutual coupling among the radiating elements is earned. The idea of total area reduction and mutual coupling reduction are verified via simulations, which are performed via 3D full-wave model, and measurements.