Epidemiological features of syphilis diagnosed at a clinic of sexually transmitted diseases Background: Syphilis continues to be a common sexually transmitted disease. Aim: To describe the epidemiologic features of patients with syphilis consulting in a Chilean sexually transmitted diseases clinic. Material and Methods: Review of medical records of patients with positive serology for syphilis, who attended a unit of sexually transmitted diseases between 2015 and 2017. Results: Of 266 cases, 61% were male and 74% were aged between 20 and 49 years. The highest incidence was observed in males aged between 20 and 30 years. Eighty five percent of cases were diagnosed in latent phases, 10% of the cases had a co-infection with HIV and 18%, a history of other sexually transmitted disease. The rate of coinfection was significantly higher in men than in women (78 and 28%, respectively; p < 0.01). Only 6.4% reported always using a condom. Men used it with higher frequency than women (72 and 28% respectively; p < 0.01). A low adherence to treatment and faulty follow-up and treatment of sexual contacts was observed. Twenty five percent of women diagnosed with syphilis were pregnant and 27% of them had a premature birth, with one neonatal death. Conclusions: A high incidence of syphilis was observed, especially in men of younger ages. The diagnosis is delayed, the treatment of sexual contacts and the use of condoms are uncommon. Although the treatment of pregnant women is appropriated, some perinatal complications are observed.