The Liebowitz's Social Anxiety Scale (LSAS) (Liebowitz, 1987) is a rating scale of fear and avoidance in social interaction (12 items) and performance-oriented situations (12 items). This paper present the study of empirical and concurrent validation of the LSAS. Ninety-six patients suffering from social phobia according to DSM IV were included and compared with 64 non-clinical control subjects. Both patients and controls were divided into two sub-groups: the LSAS passation by hetero-evaluation or auto-evaluation. Social phobics had much higher scores on anxiety and avoidance of the LSAS than control subjects, whatever the method. There were no differencies between hetero and auto-evaluation in both groups of patients and non-clinical subjects, either on anxiety or on avoidance. The LSAS correlated better with social anxiety and negative cognition in social situations than with anxiety-depression in social phobics. The French version of the LSAS showed a good empirical and concurrent validity and the scale presents a good sensitivity to change after cognitive behavioral therapy in social phobics.