Recent studies have added to our knowledge of the epidemiology of psoriatic arthritis (PsA) across various populations. Absence of a standard case definition and the relative rarity of PsA may have contributed to the paucity of available data to date. Reported prevalence estimates appear to vary more than incidence estimates. Prevalence estimates may vary as a result of differences in genetic factors, exposure to environmental factors, and study methods. Although prevalence data among different subgroups and extrapolation from clinical and laboratory data allow some inferences about the role of various potential risk factors for PsA, only one study has investigated them specifically. Overall, quality of life in PsA appears similar to that in rheumatoid arthritis, whereas available data on the mortality impact of PsA are conflicting, preventing a unified conclusion. This review summarizes recent data on PsA epidemiology.