Prison overcrowding constitutes a global problem faced by many countries. While prison overcrowding is often rooted in harsh penal policies conducted by national States and generates the same problems such as violence, lack of healthcare, hygiene and intimacy, promiscuity and little prospect of rehabilitation, different kinds of responses have been brought by States. The most efficient remedy seems to have been provided by the European Court of Human Rights. The latter has indeed required States on the one hand to adopt new penal policies of deflation, increased parole and decriminalisation, with a view to reducing overcrowding in their prisons, and, on the other hand, to establish a combination of preventative and compensatory remedies to improve the living conditions in remand prisons. Contrary to what the bulk of sceptical literature asserts, we show that such European penal and prison policies have already contributed to decreasing prison overcrowding in some EU countries.