As a result of the merger of Nippon Oil Co., Ltd. and Mitsubishi Oil Corporation in April, 1999, the asset portfolio of Nippon Oil Exploration Limited (NOEX) has not only expanded in size but also become fairly well-balanced even though the two companies were different in way of developing the upstream business. Activities of the projects of NOEX are presented in this paper focusing on operating projects. Also presented is an outline of the strategies of NOEX, as a subsidiary of a leading marketing and refining company in Japan, Nippon Mitsubishi Oil Corporation, aiming at further expansion and improvement of profitability.