UNDER A 1951 LAW, SEXUAL OFFENDERS IN THE STATE OF WASHINGTON CAN BE COMMITTED TO A STATE MENTAL HOSPITAL FOR A 90-DAY EVALUATION OR TREATMENT UNTIL THEY ARE JUDGED SAFE TO RETURN TO THE COMMUNITY. WESTERN STATE HOSPITAL'S TREATMENT PROGRAM IS BASED ON THREE PRINCIPLES: (1) DEVIANT SEXUAL BEHAVIOR IS LEARNED AND THEREFORE CAN BE MODIFIED; (2) SEXUAL OFFENDERS CAN RECOGNIZE AND CHANGE IRRESPONSIBLE BEHAVIOR PATTERNS THROUGH SELF-HELP GROUPS SIMILAR TO ALCOHOLICS ANONYMOUS; AND (3) THE HOSPITAL ENVIRONMENT MUST PROVIDE RESPONSIBILITIES AND CHOICES SIMILAR TO THOSE FOUND IN COMMUNITY LIVING. THE PROGRAM INVOLVES PEER GROUP THERAPY GUIDED BY THE PROFESSIONAL STAFF AND WORK ASSIGNMENTS IN THE HOSPITAL. COMMUNITY VOLUNTEERS ASSIST WITH SOME GROUP SESSIONS. PHASES OF THE TREATMENT PROGRAM ARE DESCRIBED IN DETAIL AND PROBLEMS ENCOUNTERED DURING 1976-77 ARE DISCUSSED. STUDIES INDICATE THAT 80 PERCENT OF OFFENDERS IN THE PROGRAM HAVE BEEN SUCCESSFULLY REHABILITATED. FURTHER EVALUATION AND RESEARCH ARE NEEDED ON PARTICULAR TREATMENT METHODS, DISCHARGE ADJUSTMENTS, AND THE PROGRAM'S APPLICABILITY TO OTHER TYPES OF OFFENDERS. RELATIONS WITH THE COMMUNITY AND OTHER THERAPEUTIC INSTITUTIONS SHOULD BE IMPROVED AND EXPANDED. THE REPORT CONTAINS STATISTICAL DATA ON THE NUMBERS AND CHARACTERISTICS OF PARTICIPANTS IN THE PROGRAM, SUMMARIES OF OBJECTIVES AND TREATMENT PROCESSES, AND A STAFF DIRECTORY. (MJM)