The purpose of this study was to investigate the effect of therapist self-disclosure in a clinical setting. In addition, the study investigated theoretical variables related to self-disclosure in psychotherapy. Therapist empathy and disclosure about norms, which have been hypothesized to be involved in self-disclosure, were included. Fifty-four adult clients of an outpatient mental health center were randomly assigned to six experimental groups. Clients in the norm-disclosure/ empathy condition were interviewed by a therapist who gave disclosure about norms for the frequency of the client's problem and made statements of empathy. Clients in the norm-disclosure/no-empathy condition were interviewed by a therapist who gave disclosure about norms but made no empathy statements. Clients in the self-disclosure/empathy condition were interviewed by, a therapist who told about a personal experience which was similar to the client's and made empathy statements. Clients in the self-disclosure/no-empathy condition were interviewed by a therapist who disclosed about personal experiences but made no empathy statements. Clients in the no-disclosure/empathy condition were interviewed by a therapist who made empathy statements but did not disclose. Clients in the no-disclosure/no-empathy condition were interviewed by a therapist who made neither disclosure nor empathy statements.