Lymphogranuloma venereum (LGV), also known as lymphopathia venerea, tropical bubo, climatic bubo, strumous bubo, poradenitis inguinales, Durand-Nicolas-Favre disease and lymphogranuloma inguinale, is a sexually transmitted disease caused by the invasive serovars L1, L2, or L3 of Chlamydia trachomatis. LGV was first described by Wallace in 1833 and again by Durand, Nicolas, and Favre in 1913.

LGV is primarily an infection of lymphatics and lymph nodes. Chlamydia trachomatis is the bacteria responsible for LGV. It gains entrance through breaks in the skin, or it can cross the epithelial cell layer of mucous membranes. The organism travels from the site of inoculation down the lymphatic channels to multiply within mononuclear phagocytes of the lymph nodes it passes.

In the United States, Europe, Australia and most of Asia and South America LGV is generally considered to be a rare disease. However, a recent outbreak in the Netherlands among gay men has led to an increase of LGV in Europe and the United States. A majority of these patients are HIV co-infected. Since the 2004 Dutch outbreak 341 cases have been reported in the UK and 80 cases in the US, but infectious-disease experts fear the actual number is substantially larger because this form of chlamydia is difficult to diagnose and many physicians are not aware of its existence.