This section is devoted to the analysis of specifity of exceptio praejudicii. The author notes that the usual provisions do not apply to the exceptio praejudicii. The specific nature of this objection, acting as a regulator of claims competition result in direct disagreement with stereotypic understanding. Usually at the disposal of the claimant is the only one claim, but here, in the scope of exceptio praejudicii, there is an exceptional case: several claims are provided to the claimant for achievement of the same purpose (plures actiones ejusdem rei nomine). Exceptio, depriving the claimant of one of the remedies can not leave him in defenseless position, and therefore protection is always guaranteed by other means. In case of exc. praejud. there can be no question of that process, judicium, is defective and unacceptable: the claimant obtained formally correct formula petitoria, confessoria, etc., the process is started unhesitatingly and immediately, litis contestatio is established, and the claimants’ demand is rejected by a legally effective court decision. 

Keywords: history of civil procedure; the Roman civil process; claims competition; praejudicium; praejudice; issue preclusion.