The Sex Offender Treatment Rating Scale (SOTRS) is proposed as a potential process and outcome measure for cognitive/behavioral sex offender treatment. Therapists complete a 6-point rating scale with behavioral descriptors of Insight, Deviant Thoughts, Awareness of Situational Risks, Motivation, Victim Empathy, and Offense Disclosure. The ratings are combined to produce a single treatment progress score. Pairs of therapists providing treatment for 122 court-referred male sexual offenders in 15 therapy groups independently completed the SOTRS twice, at 5-month intervals. The results showed that internal consistency, interrater agreement, and test-retest reliability were all high. While further studies are needed to validate the SOTRS against recidivism criteria, it can presently be used for staff development, treatment planning, program evaluation, and quality assurance objectives.