Lambda-(BEDT-TSF)2GaCl4 has revealed to be a new organic superconductor, where BEDT-TSF is bis(ethylenedithio)tetraselena-fulvalene. The onset temperature of the superconducting transition was about 9.5K and the mid-point transition temperature (T(c)) was 8 K. The crystal belongs to triclinic system. BEDT-TSF molecules are arranged to form a ''quasi-stacking structure,'' where four molecules form a repeating unit.