Much of the literature on negotiation focuses on the effect that various personality factors, characterizing the parties or mediators involved in the process, have on negotiation outcomes. Nevertheless, there hardly can be found a study, which examines these factors with psychometrically reliable and valid tools. The present study uses psychodiagnostic projective method for measuring the personality trait known as integrative complexity, which is considered as a basic factor that connects cognitive traits to attitudes toward conflict resolution. In a sample of 26 Israeli students this trait, assessed by two Rorschach measures - the blend responses and the frequency of organizational activity - has been revealed as a personality characteristic that might explain seeking compromise agreements in negotiation. Individuals low in integrative complexity tend to rely on highly competitive and less cooperative tactics much more than highly integrative complex individuals. Projective measures for integrative complexity, assessed in this study, are suggested to test people as they are assigned to teams charged with important tasks involving complex group decisions and negotiation. In future studies of complex group decisions this psychodiagnostic approach might be used as a part of the support systems in the process of group negotiation.