The business judgement rule is an important defense which, if applicable, reduces the liability exposure of directors to claims for mismanagement and breach of their duty of care. This defense recognizes that not all decisions by directors will result in benefit to the corporation or will appear to be prudent. However, courts will not second-guess business decisions by directors so long as the directors follow appropriate procedures in making decisions. In essence, the business judgement rule provides that courts should not examine the quality of the directors` business decisions, but only the procedures followed in reaching the decision, when determining director liability. This article analyses the case relating to the business judgement rule, and studies whether the rule may be applied to the Korean company law. The article includes i) policy reason for rule, ii) preconditions to application of rule, iii) presumptive effect and rebutting the presumption, and iv) application to special situations. Its conclusion is that the business judgement rule is not peculiar to American law, and Korean case may be based on a similiar position.