Psoriatic arthritis is a common chronic rheumatic disease that may result in considerable joint damage if left untreated. Recent clinical studies have focused on the identification of poor prognostic factors. Early, aggressive treatment is indicated in patients with significant joint inflammation and certain HLA antigens. Immunopathogenic evidence continues to point toward an HLA class I-mediated disease with perhaps an important role for CD8+ T cells. Although few basic research publications discuss psoriatic arthritis, studies in the areas of spondyloarthropathy and psoriasis continue to shed light on disease mechanisms. Greater collaboration is advocated among researchers in these areas and those interested in achieving a better understanding of the disease pathogenesis of psoriatic arthritis.