The extent of the crime problem in Korea is not as serious as in other industrialized countries, particularly regarding the violent crimes of murder and robbery, although the crime rate has increased rapidly in recent years. The average arrest rate is approximately 90 percent. Newly emerging crimes are computer offenses, drug-related offenses, and organized crime. Organizations that investigate crimes in Korea are divided into two categories: prosecutors and judicial police officers. Public prosecutors have the authority to investigate criminal cases. The judicial police officer also has authority to conduct criminal investigations, but under the supervision of the public prosecutor. Special judicial police officers handle specific types of cases specified in law. To deter unlawful arrests or detentions, the chief prosecutor of a district or his/her representative inspects police records and questions arrestees or detainees monthly. Prosecutor offices receive all police requests for an arrest warrant and then determine whether the request should be passed on for judicial action. This procedure also applies to search warrants. Emphasis is given to the independence of prosecutors under law, so as to protect their work from political influences. Korean prosecutors have the authority and the duty to investigate all crimes; however, most of the criminal cases are managed and conducted by judicial police officers rather than prosecutors; prosecutors screen the cases to ensure that police efforts are in accordance with the law. This paper details the case screening procedures of Korean prosecutors. An overview of the discretionary power of prosecutors in case screening focuses on the criteria by which discretionary decisions are made, reasons and procedures for suspension of prosecution, and control of the prosecutor's discretion. The author advises that by being the supervisors of criminal investigations, prosecutors can make more effective decisions in case processing and conduct more efficient prosecutions. The paper recommends that the functions of Korean prosecutors be expanded to include issues of international cooperation in dealing with transnational crime. Appended crime tables