Much of what is presently known about stalking in a domestic context has been depicted by the popular press, typically following a tragic outcome, and suggests that it is a problem of increasing dimensions. However, scientific literature on this subject is quite limited. This article provides an overview of scientific data related to stalking and associated psychiatric syndromes, including erotomania. It reviews the current antistalking legislation and the National Institute of Justice Model Anti-Stalking Code. Four case studies of stalkers with psychotic disorders versus personality disorders are presented, and the differential diagnoses are discussed. The implications of diagnostic classification, with respect to criminal responsibility, are also discussed.