Stalking is a widespread phenomenon describing a pattern of intrusive and threatening behavior that leads to the victim's perception of being harassed, threatened and frightened. Physical assault and even homicide may sometimes occur in the context of stalking. For psychiatry the following tasks result: (1) diagnosis and classification of stalking cases, (2) risk assessment of stalking cases, (3) counselling and treatment of victims of stalking and, (4) treatment and assessment of stalkers. Empirical findings and instructions are presented for these four areas.