The article analyzes the principles of criminal responsibility and sentencing and the specific features of their application to crimes committed in complicity. In particular, according to the general rule, the commission of an act that has all the symptoms of the criminal structure provided for in the Criminal Code is the basis for prosecution. In crimes committed in participation, these signs are manifested only in the actions of the perpetrator. On the other hand, the organizer, agent and assistants do not directly participate in the crime committed by the executor, that is, they do not commit the actions of the objective side of the crime, which constitute the structure of this crime. The article states that it is not difficult to determine responsibility for crimes committed by one person or co-perpetrators, but there are certain difficulties in determining their responsibility when the crime is committed with the participation of several people or by an organized group or criminal association. Also, the views and opinions of scientists on the issue under analysis were studied, and the problems in this area were identified, as well as proposals and recommendations were developed for determining the scope of responsibility for participation in the crime, imposing punishment based on the level of social danger of each participant, and improving the legislation.