In the Russian legal system, the understanding that justice should be not only timely, but also fast enough has matured for a long time. The delay in the investigation of a criminal case and its consideration by the court allows the guilty to avoid the deserved punishment in some cases, which calls into question the principle of inevitability of punishment on the one hand, and hinders the right to access justice, on the other hand. The term reasonable time for legal proceedings has emerged as a requirement of international law to be tried without undue delay. The right to a reasonable period of criminal proceedings is regulated by Article 6.1 of the Code of Criminal Procedure of the Russian Federation, but this norm is not fully implemented to date, as evidenced by the decisions of the European court of human rights issued on complaints of violation by the Russian Federation of the provisions of the European Convention for the protection of human rights and fundamental freedoms. At the same time, the available research considers the requirement of reasonable terms in criminal proceedings from the standpoint of criminal procedure law, which is not fully justified. The article attempts to consider the problematic issues of reasonable terms of criminal proceedings from the perspective of criminology, as a science that has incorporated theoretical and practical issues of fighting crime, as well as the problems of criminalistic criteria in criminal proceedings.