In this paper a novel reconfigurable antenna array for 2X2 adaptive MIMO systems is proposed. The array is composed of two reconfigurable slot antennas located at upper-right and upper-left corners of a PCB, where each antenna element consists of a right-angled slot, PIN diodes, lumped capacitors, and bias networks. By carefully controlling these diodes, the induced current distribution around the slot can be changed, resulting in different radiation patterns. Owing to the compact size and ease on manufacture, the proposed antennas can be a promising solution for adaptive MIMO systems in handheld devices such as smart phones and notebook computers.