The misinformation effect states that when subjects are given verbal misleading postevent information after viewing an event, their memory for that event is seriously deteriorated. In this article, studies on the misinformation effect in the field of eyewitness research since Loftus (1974) are reviewed. First, the effects of postevent information and the research methods which were established and developed by Loftus and her colleagues (e.g., Loftus, Miller, & Burns, 1978) are introduced. Second, the modified recognition test developed by McCloskey & Zaragoza (1985a) to criticize the standard original recognition test is addressed, followed by a review of studies in which the modified recognition test was used to examine the misinformation effect. Third, studies examining the modified recognition test itself are scrutinized. Lastly, studies (e.g., Zaragoza & Lane, 1994) which introduced the source monitoring approach are reviewed. Theoretical positions such as the substitution hypothesis, the coexistence hypothesis, the bias hypothesis explaining the misinformation effect are also considered.