The article deals with the issue of providing adversarial criminal proceedings proving during the preliminary investigation on the basis of competition and freedom to provide their court their evidence and to prove to the court their credibility, guaranteeing fairness and legality of the judgment. Ways of improving the competitive procedure of proving it was during the pre-trial investigation and thereby ensure implementation adversarial pretrial proceedings, including: 1) consider the private prosecutor and the victim pursuant to significantly expand the scope of its procedural rights that would enable better integration of legal position of the victim in criminal proceedings has no display of arms than petitions and speeches in the debate; 2) extension of the jurisdiction of the court in pre-trial stage of the process by providing the court office is currently entrusted to the preliminary investigation to address requests by the defense for legal proceedings; 3) submission of the defense objections to obvynuvalnyy act, the act of folding protective material after the opening of proceedings that may be filed with the Court and the Prosecutor announced after a guilty act.

Keywords: evidence, competition, party, pre-trial investigation, judicial control function, the investigator, the victim, сounsel.