The article presents probably the most relevant research to date on the Slovene prison system. The study was conducted through a 2-year research project sponsored by Ministry of Justice and carried out by the Institute of Criminology in Ljubljana. Along with a "longitudinal" study of the social climate in Slovene prison institutions, it evaluates the concepts, practices, and results of so-called sociotherapy as a specific approach to treatment of offenders. "Specific" in this case means that treatment simultaneously encompasses life in prison, the offenders' social environment, and the inclusion of prison staff. Sociotherapy began as an experiment during the mid-70s and led to astonishing results, namely, the "opening" of prison institutions for almost all inmates, regardless of the length of sentence or the crime committed. Applying the findings of sociotherapy every 5 years since 1980, the social climate in every Slovene prison institution has been measured to assess the quality of support and control prisoners receive and the discipline and treatment philosophies at work in the system. Finally, the article deals with the situation after Slovene independence in 1991 and the passage of new legislation. Against expectations, we find that with the advent of democracy, standards of prisoner treatment have dropped. However, the success of the experiment should encourage all countries seeking to reduce the significant costs of incarceration and attempting to make prison institutions more humane. (Published Abstract)