The 1979 Islamic Revolution in Iran which led to the emergence of a revolutionary, anti-Western, anti-establishment regime under the tutelage of Shi’ite ulema radically changed the previous state of relations with Saudi Arabia, a conservative, Sunnite, pro-West monarchy and junior partner of the defunct Pahlavi State in the security system in the Persian Gulf. The present article intends to look into the state of bilateral relations between the two countries since 1979. The article argues that the relations between these two important Muslim and regional countries have been affected by their constant rivalry in a number of fields considered critical to both of them. As analyzed here, the contest between them in all these areas have been conducted in a rather limited manner, and that both sides have exercised restraint to avoid spiraling into “unlimited contest.” The “limited nature” of contest in fact allowed gradual reduction of tension between them and led to détente and even expansion of cooperation in late 1990s. The détente period came to an abrupt end in the wake of the traumatic aftershocks of 9/11, particularly the U.S. occupation of Iraq. Having looked into the afore-mentioned dominant pattern of relations between Iran and Saudi Arabia since 1979, the authors posit that adoption and pursual of a positive, proactive approach by the two sides and reliance on confidence-building measures can indeed help diffuse the on-going tension and mutual suspicion and pave the way for the promotion of mutually-beneficial policies and measures. In their analysis, the two sides, despite all the differences and difficulties, enjoy the potentials to decide to explore practical ways and means on how to define shared interests, goals and objectives.