Study data derive from records of 150 recidivists under protective supervision, 100 recidivists placed in social readaptation centers after failure of protective supervision, and responses of 280 probation officers surveyed about the efficiency of preventive supervision. Analysis of records suggests that the success of protective supervision is influenced by the nature of the offenders' crimes, the place of supervision (i.e., city or town), the diligence of the probation officer, the stability of recidivists' employment during protective supervision, and marriage. In the estimation of officers for supervised release, the most important conditions for successful protective supervision are, a paid job or professional training, the obligation of self-maintenance, consistent sobriety, medical treatment as needed, avoidance of criminal environments, and community service requirements. The most difficult obligations for officers to enforce is detoxification cures for alcoholics with abstinence in second place. The most difficult recidivists to resocialize are nonproviders, family abusers, alcoholics, perpetrators of violent theft, recidivists punished for theft, and swindlers. An honest, healthy, and cooperative family and a supportive working situation are essential factors to recidivists' positive development. Also crucial are a positive attitude of the supervising probation officer toward clients and the ability of officers to make changes in treatment instructions as needed. The most frequent causes of failure are refusal to work, alcohol abuse, inability to maintain oneself, avoidance of the supervising officer, refusal to detoxify, and change of domicile without permission. Factors with a decisive role in resocialization are rapid adjustment to work, a normal, positive family, rapid acceptance of supervision and frequent supervisory contacts, the promise of a room, distance from criminal influences, material assistance, and medical treatment. In general, protective supervision is deemed very effective by 28.6 percent of the supervising officers and sometimes effective by 62.9 percent of the officers.