In this article the psychodynamic link between loneliness and sadism is examined on basis of a case report of the sadistic and cannibalistic serial killer Jeffery Dahmer. Envy, shame/rage mechanism, a disturbed oral-sadistic development, castration fear and severe feelings of inferiority, the conviction of being unlovable and unacceptable, need to diminish tension, powerful and sadistic fantasies as a consequence of inadequate and frustrated parenting, and reality distortion appear to be involved in sadistic etiology.