We fabricated an organic light-emitting field effect transistors (OLEFET) using a co-deposited layer of TPTPT and NTCDA which has p-type and n-type semiconducting behaviors, respectively. The organic layer was formed on a comb type electrode (source-drain electrodes) with a channel length of 25μm on a p-Si/SiO₂ substrate. Bipolar and EL characteristics were investigated by changing co-deposition ratio of TPTPT and NTCDA. In the optimum deposition ratio, we observed typical ambipolar characteristics, demonstrating saturation current characteristics at low V_d (source-drain voltage), followed by divergent current characteristics at high V_d.