The United States and Iran as former allies turned into adversaries after the Islamic Revolution of 1979. Since then the United States has tried to contain Iran as a state considered to be a threat to the U.S. national security. The U.S. Congress has also acted in line with the administrations’ policies and in some cases directed the administration to take a tougher stance toward Iran. A review of the literature on congressional studies indicates that the power of individual actors in legislative policymaking has increased since the 1970s. Using the Bounded Rational Model in foreign policy decision making, the present paper attempts to explain the decision making behavior of congressional sanction bill sponsors for the two financial/banking sanction laws against Iran during the Obama administration. These two laws are the Comprehensive Iran Sanctions, Accountability and Divestment Act of 2010 and Section 1245 of the National Defense Authorization Act of 2012. The method of qualitative content analysis is employed to explain the context of the bills and the sanction triggers and goals are identified through the remarks of bill sponsors. The analysis of these sanction laws using the four elements of actor, preference, structure, and decision criteria indicates that the Bounded Rational Model as it takes into account the decision makers’ cognitive limitations and the limitations imposed on them by the environment of decision making is a good model to explain the decision making behavior of banking sanction bill sponsors.