The phenomenon of homeless people is eliciting a devastating social impact with an estimated prevalence in the USA and in Europe between 5.6% and 13.9%. These persons have a poor quality of life, a limited or no social life. They are often unemployed or work only occasionally. They are at risk for problems with the law and often suffering from addiction to other drugs, psychiatric and other medical diseases. Alcohol is often not the cause of their social status, but only the result of other discomforts thus contributing to their bio-psycho-social degradation. In 2009 the US Department of Housing and Urban Development’s Homelessness Assistance Programs and in 2010 the European Consensus Conference on Homelessness discussed about the social rehabilitation of these people, using the concept of case management. In particular, the Standard Case Management was able to improve the housing stability, to reduce the use of drugs and to remove the working barriers. The Assertive Community Treatment was able to improve the housing stability and had a better efficacy for patients suffering from double diagnosis.