1. This paper has dealt with the definition of the term sexual psychopath (and suggested alternatives), with special reference to the difficulties that have been encountered in applying it for legal purposes.2. The range of psychiatric opinion as to the definition and possible applications of the term is so broad and the relevant scientific data and formulations so tentative, that the term is nearly meaningless for diagnostic purposes.3. The term sexual psychopath is used by psychiatrists not as a specific diagnostic label, but as a descriptive term necessary for administrative purposes. Social maladjustment in the sexual sphere is the main criterion for application of the term.4. Therefore, until psychiatric nomenclature is further refined, it is important that tentative, clinically useful terminology relating to sexual personality pattern disorders not be forced into legal statutes as final and definitive.5. There is a distinction between psychiatric and legal concepts and definitions f sexual abnormality. While psychiatry is concerned with the entire range of sexual behavior as clinical phenomena, either overt behavior or latent or repressed tendencies, the law is concerned only with sexual behavior that is dangerous or morally offensive.6. Legal definitions of sexual psychopath make use of both psychiatric and legal terms but these terms are not themselves specific enough to justify their use in legal finding.7. The sexual psychopath laws, based on inexact psychiatric terminology, have proved to be as ineffective administratively as the criminal sex laws.8. Efforts to correct current unsatisfactory sex legislation take 2 main forms: (a) clarification of definitions in present laws, and (b) formulation of new legislation that will provide psychiatric consultation but will not depend for its application upon precise diagnosis.9. Even though psychiatric concepts and definitions in the area of antisocial sexual behavior are still in the formative stage, psychiatric consultative services appear to offer the most fruitful approach to the problem of the sex offender.