We present the case of proctitis due to Streptococcus pyogenes and Chlamydia trachomatis, acquired by sexual transmission, in an immunocompetent patient. Sexually transmitted infections (STIs) are becoming more frequent and this possibility must be taken into account in the differential diagnosis of the causes of proctitis. The most frequent causative agents are Chlamydia trachomatis, Gonococcus, Herpes simplex virus and Treponema Pallidum, however, Streptococcus pyogenes infection should be assessed even in immunocompetent patients. It is important to consider sexually transmitted infections as a cause of proctitis to avoid a delay in antibiotic treatment and the development of complications.