A series of recent epidemiological studies has assessed the prevalence of personality disorders in the general population. However, all these reports run a serious risk of overestimation. First, all research is based on problematic definitions in DSM-IV-TR, both for overall PD and for specific categories. Second, all studies suffer from a failure to distinguish problematic traits from clinical disorders. Third, many methods of assessment have been inadequate to make diagnostic decisions requiring subtlety and clinical experience. Overestimation of prevalence negatively affects research, which would benefit from a narrower definition of PDs based on dysfunction in multiple domains.