The number of syphilis cases has been increasing in the UK, partly because of localised outbreaks. The sharpest rises have been among men having sex with men, but the incidence among heterosexuals has also risen. Blood-test screening for syphilis is an important part of sexual health, and includes routine screening of pregnant women at the first antenatal visit. Prompt treatment with penicillin in the earlier stages can stop the progression of the disease. Unfortunately, public awareness of syphilis and its potentially serious consequences is low. It is important for health professionals to be alert for signs of the disease and to initiate tests if there is a likelihood that a patient has or is at risk for the disease.