The article studies problematic issues of illegal income legalization or money-laundering which law-enforcement and financial organs in the CIS countries confront. Not only the CIS but the whole civilized world is struggling with legalization (money-laundering) of the income generated as a result of crime activities. According to the International Monetary Fund, the total sum of "dirty" money currently circulating in the world amounts between 500 billion and 1.5 trillion American dollars which conforms due to different estimates 2-5 percent of the world gross domestic product. The article studies problems concerning prevention and combating legalization (money-laundering) of the income generated as a result of criminal activities which law-enforcement and financial units come across in the CIS countries. The author focuses on establishing the definition of this socially negative phenomenon which forms an essential part of illegal activities of organized crime. Both common and specific characteristics of the battle against money- and other property-laundering generated as a result of criminal activities which are typical for the CIS countries are presented here. Legalization of the income generated as a result of criminal activities (money-laundering) is a component of any criminal activity and an important part of the criminal economical circle. The combat against legalization of the illegal income includes research, exposure and neutralization of the financial component in the activities of organized groups and criminal organizations. Moreover, effective ways of fighting that type of crime are suggested based on analyses of the law currently in force, practical work of financial intelligence units, and scientific research. (Published Abstract)