Social phobia is a relatively unrecognized disease. This ignorance is partly due to border troubles, as timidity, troubles between the norm and the pathologic, between psychiatry, psychology and sociology. Many other disorders appear to be differential diagnosis and question about nosographic limits of social phobia. After the description of the semiology, the authors suggest a review of differential diagnosis by explaining each diagnostic criterion of social phobia. Then the therapeutic side of the question will be tackled, mainly about cognitive-behavioural therapy and drugs used in France.