Syphilis is a systemic infection caused by Treponema Pallidum spirochete, which is considered to be the main sexually transmitted disease. The genital ulcerations and local inflammation found in syphilis are favouring factors involved in transmitting the HIV infection. Recent data suggests that individuals suffering from other sexually transmitted diseases are 3 to 5 times more exposed to developing HIV infection. On the other hand, simultaneous HIV infection may worsen the syphilis evolution. In the light of this data we present the case of a patient with syphilis-HIV coinfection recently diagnosed and we will summarize the clinical and evolutive features of the syphilis-HIV coinfection