Sexually transmitted diseases (STD) constitute a frequent presenting complaint. The epidemiology of human immunodeficiency virus (HIV) infection is identical to that of STD and must therefore be systematically investigated in the presence of any STD. Chlamydia trachomatis (CT) is involved in the majority of cases of urethritis and epididymitis in young subjects and is present in the urethra of 10% of subjects with a genital ulcer. Genital ulcers are due to either Treponema Pallidum, Haemophilus ducreyi, or Herpes simplex virus: there is little clinicobacteriological correlation and it is therefore essential to perform laboratory examinations in order to establish the diagnosis. The prevalence of venereal vegetations due to HPV viruses has increased markedly over recent years and require effective treatment and surveillance because of the risk of carcinoma induced by viral oncogenesis. Other viral diseases such as hepatitis B are also classified as STD. The main diagnostic techniques used at the present time for each STD are reviewed and the consensually accepted therapeutic protocols are also proposed.