The hypothesis that a connection exists between the personality defenses of interacting individuals and their attitudes toward and perceptions of their interaction is explored by assessing the defense mechanisms of a group of Ss to psychosexual stimuli, the Blacky Pictures, and evaluating their interaction when pairs of Ss are engaged in a task which arouses a specific psychosexual disturbance. The results indicate that the interaction of two people who project the same psychosexual impulse is more negative than pairs of people who use other defenses. Dissimilar defenses do not seem to adversely affect the interaction; however, when both partners have high conflict, more negative interaction tends to result than when only one is disturbed. The relative hierarchies of defence mechanisms and psychosexual dimensions, with regard to their effect on interpersonal relations are discussed.