The presence of peripheral arthritis and HLA-A, B, C, DR, and DQ antigens was evaluated prospectively in 18 Caucasian men with human immunodeficiency virus-associated psoriasis. An asymmetric polyarthritis occurred in 32% of the patients and correlated with the presence of HLA-B27. Extensive clinical overlap between psoriatic arthritis, psoriasis, and Reiter's syndrome was noted. No significant excess of the HLA antigens previously found to be associated with psoriasis was seen, which suggests that human immunodeficiency virus-associated psoriasis per se may instead constitute another form of spondylarthropathy that is more closely related to Reiter's syndrome.