Client-therapist verbal interaction in content analysis research has just begun to be defined. Reciprocal Category Analysis (RCA) is used to measure therapeutic interactions between client and therapist. Three experienced therapists from each of the schools of client-centered, Rational Emotive (RET), Transactional Analysis (TA), and Gestalt therapies submitted 30-minute audiotapes of therapeutic interaction. Fifteen minutes of therapy were randomly selected from each of the 12 tapes and analyzed using Morgan's RCA. Amplification regarding ideas or problems, common to all therapies, was more predominant in Client-centered Therapy. RET, TA and Gestalt used more variety of talk than Client-centered; the sequence of the interactions varied among them. RET had the most verbal interchanges between therapist and client, and Client-centered the least. Silences were most predominant in Gestalt and almost absent in Client-centered psychotherapy. Interpretations, corrections by the therapist, or client or information exchanges were utilized infrequently by all psychotherapies. (Data do not refer to quality of exchanges but to observable verbal events and sequences of events which occurred in the psychotherapy sessions.) Except for Client-centered therapy, the quantity of the talk did not differ among the psychotherapies; however, the patterns and sequences were different. (Author/NRB)