The article considers the possibility of separation of cases on the basis of theorize, analysis of legislation and judicial practice. Introduction of the jury trial showed peculiarities of the RF Criminal Procedure Code implication in cases tried by jury. These peculiarities emerge when decision is made on severance of criminal case. The necessity to address this issue occurs when some accused do not file a motion to be tried by jury. In relation to such accused who waived a jury trial, the investigator or the judge separates a criminal case. If it is not possible the case is considered by the jury trial. This rule is established for actions of the investigator during familiarization of the accused with materials of the case and for the actions of the judge in the preliminary hearing. The author comes to the conclusion that regardless of the decision of the investigator, the judge must consider the possibility of severance of the case, if the case involves the accused having different positions in relation to the jury trial. At the stage of preliminary hearing the court must decide on separation or integration of criminal cases, but not return the case to the prosecutor on these grounds. This is consistent with the general rules of separation of criminal cases and the specifics of the proceeding in jury trial.