A MULTIMODAL MILIEU TREATMENT APPROACH WAS ASSESSED IN A PRISON SETTING BY USE OF THE MINNESOTA MULTIPLE PERSONALITY INVENTORY. THE PARTICIPANTS HAD A MEAN AGE OF 41, FOUR PRIOR INCARCERATIONS, AND DOCUMENTED DIFFICULTY WITH ALCOHOL ABUSE TO THEIR INCARCERATION. INTENSIVE TREATMENT WITH A METHOD DESCRIBED IN DETAIL IN THIS STUDY BROUGHT ABOUT BEHAVIORAL IMPROVEMENTS IN THIS GROUP OF INDIVIDUALS WHO TRADITIONALLY HAVE AN UNFAVORABLE PROGNOSIS. DURING TREATMENT THERE WAS AN ABSENCE OF ACTED-OUT AGGRESSIVE BEHAVIOR AND NO MAJOR INFRACTIONS OF INSTITUTIONAL POLICIES AND REGULATIONS, DESPITE THE FACT THAT MANY OF THE PARTICIPANTS HAD BEEN CONVICTED OF VIOLENT CRIMES AND SOME HAD BEEN FLAGRANT VIOLATORS OF INSTITUTIONAL RULES PRIOR TO PROGRAM ENTRY. LONG-RANGE EFFECTS WERE ALSO FAVORABLE, WITH A MUCH REDUCED RECIDIVISM RATE COMPARED TO NON-TREATED ALCOHOLIC OFFENDERS. A BIBLIOGRAPHY (19 ENTRIES) IS APPENDED.