Although the field is young, studies pertinent to genetic hypotheses have accumulated for several personality disorders. Genetic links to personality disorders from the domains of normal personality and Axis I disorders are reviewed. Evidence of a link to schizophrenia is clearest for schizotypal and less conclusive for paranoid and schizoid personality disorders. A genetic association between borderline personality disorder and affective disorders has not been clearly supported, but there may be a subtype genetically linked to affective disorders. Evidence of genetic influence is mixed for obsessive-compulsive personality disorder. In general, greater attention to dimensional phenotypic measures and multivariate designs can yield more definitive answers regarding the correct subtyping and probable etiology of personality disorders.