The recent European literature on surgical castration in treatment of sex offenders is reviewed. Results are reported of the most important empirical studies conducted in this field of sex research in Germany, Switzerland, Norway, and Denmark. Methodological problems of follow-up studies on castrates as well as the subject of castration as treatment for sex offenders as a whole are discussed. The main conclusion is that there is no scientific or ethical basis for castration in the treatment of sex offenders.