This study uses a series of CGCM (coupled atmosphere-ocean general circulation model) experiments to examine the importance of air-sea interactions to Madden-Julian Oscillation (MJO) in the Indian-Pacific Ocean sectors. A total of three CGCM simulations are performed: the Pacific Run, Indo-Pacific Run, and Indian-Ocean Run. In each CGCM run, air-sea interactions are restricted to a certain portion of the Indian-Pacific Ocean by including only that portion of the ocean in the ocean model component of the CGCM. The Pacific Run includes only the tropical Pacific Ocean in the CGCM; the Indian-Ocean Run includes only the Indian Ocean in the CGCM; and the Indo-Pacific Run includes both the Indian and Pacific Oceans in the CGCM. Our CGCM results indicate that (1) Pacific air-sea interactions affect the propagation feature of MJO and (2) Indian Ocean air-sea interactions affect MJO intensity. In particular, the MJO intensity in the central subtropical Pacific is affected the most by the Indian Ocean.