Lymphogranuloma venereum (LGV) is a sexually transmitted infection that is causing an ongoing epidemic in men who have sex with men (MSM) in Europe, the United Kingdom, and North America. Twenty-nine rectal swabs positive for Chlamydia trachomatis were analyzed by real-time PCR for the presence of LGV serovars. Genotyping revealed an identical L2b serovar from four specimens. All patients were MSM and human immunodeficiency virus infected. Three of the four presented with severe ulcerative proctitis. We report a cluster of rectal LGV serovar L2b infections in Sydney, Australia.