A 44-year-old man who has sex with men presented with a three-month asymmetrical polyarthropathy. He had a positive HIV-1 antibody test consistent with infection acquired more than six months previously. Lymphogranuloma venereum (LGV)-associated DNA was detected from a rectal swab. Following successful treatment for LGV his arthritis resolved completely. Infection with HIV-1 has been hypothesized to cause reactive arthritis but this has been disputed. The most likely diagnosis in this patient was sexually acquired reactive arthritis secondary to LGV infection. As LGV can be asymptomatic and treatment differs from that of the other serovars, screening should be considered in all men who have sex with men (MSM) presenting with acute arthritis, particularly if they are HIV infected.