The concept of psychopathy is important to researchers, clinicians, decisionmakers, and offenders who work or are confined in the criminal justice system. This article attempts to inform the conceptualization and measurement of psychopathy as a dimension or a taxon by highlighting the underlying assumptions of dimensional and taxometric measurement approaches, reviewing their strengths and weaknesses and discussing methodological problems in existing studies. Four conclusions can be drawn from this review. First, there are relatively few studies that have assessed the structure of psychopathy specifically as taxonic or dimensional. Second, methodological inconsistencies of the taxometric studies conducted thus far have potentially contributed to mixed findings regarding the structure of psychopathy. Third, no study to date has conducted both dimensional and taxonic analyses with the same sample in order to compare the two approaches directly. Lastly, although it appears that dimensional analyses have yielded more consistent results than taxometric analyses have, it would be premature to conclude that either approach has uncovered the true structure of psychopathy, given the few studies conducted to date and the differences among them. Table, notes, and references