This document describes using consensus methods to improve agent's knowledge in multiagent decision support systems. The problem of improving agent's knowledge, structure of decision, profile and criterions of consensus determining are presented in first part of article. Next a two stage algorithm of consensus determining was elaborated. This algorithm, among other things, allow to shorten the period of time necessary to take a decision, to limit the risk associated with this process and leads to increased effectiveness of decision taking since solutions generated by agents of inadequate level of knowledge are not taken into account.