As many other countries, We have ‘presentence investigation system’ in Korean criminal justice system. But, in comparison with other country’s system like America or England, our system is imperfect. That is to say, our presentence investigation system is legally applied only to juvenile criminals. In addition, though Korean probation and parole office have the power of presentence investigation, this power is not effectively used. So, legally, adult criminals have been sentenced in a court without presentence investigation process. And consequently, their mental disorder, home background, social environment, the cause of crime and so on are not precisely considered in a court. So, such sentencing have some problems that is unscientific, regimental, and none effective to criminal’s treatment and rehabilitation. Fortunately, Presidential Committee on Judicial Reform has made a law about presentence investigation, but this law also have many problems. That is to say, this law rules the subject of presentence investigation dualistically - court official and probation officer. Such system is not discovered in any other country, and this may cause chaos of presentence investigation process and may result in the squandering of national budget. So, this article indicate the importance of complete presentence investigation system and that we should made a law of presentence investigation system more systematically and unitarily.