Lymphogranuloma venereum (LGV) has recently been reported in men who have sex with men. In a case-control study we compared behavioural and clinical features of 32 men with LGV (cases) and 31 men with non-LGV chlamydial proctitis (controls). LGV was associated with rectal discharge (odds ratio [OR] 4.15, 95% confidence interval [CI] 1.42, 12.2), and there was a tendency to association with HIV infection (OR 3.60, CI 0.67-19.4), sexual contact in the UK (OR 3.03, CI 1.02-9.01) and fisting (OR 5.04, CI 0.98-26.1). LGV should be considered a possible diagnosis in men with rectal discharge.