The effects of treatment format and client personality dimensions upon responsivity to cognitive therapy were investigated. Depressed subjects were assigned to either 12 weeks of individual or group cognitive therapy. The two formats were found to be equally effective in significantly reducing depression. Subjects were categorized at pretreatment using Beck's Sociotropy/Autonomy Scale in conducting a post hoc analysis of the impact of client personality dimensions upon responsivity to treatment. Consistent with Beck's (1983) interactional model, sociotropic subjects who received group therapy and autonomous subjects assigned to individual therapy showed greater improvement than subjects whose predominant personality dimension did not match the type of treatment received.