Organic thin film transistor (OTFT) is the basic device for building analog and digital circuits and systems on a flexible substrate. Our studies show that, complementary design logic (CMOS), which is most common in MOSFET circuit design, is not suitable for OTFT circuits. In this work, we propose a new design logic that fits the characteristics of OTFT devices. Considering the fact that the mobility of the p-type OTFT is much better than the n-type OTFT, the proposed design logic uses mostly p-type OTFTs to implement logic functions. Circuit simulations have been done to compare the proposed design logic with other existing ones. The results show that the proposed design logic can improve the performance of the circuit by 2/spl sim/4/spl times/, lower the energy dissipation by 2/spl sim/6/spl times/, and reduce the circuit area by 2/spl sim/10/spl times/.