BACKGROUND: Selective serotonin reuptake inhibitors are effective in the treatment of social anxiety disorder and are currently regarded as the pharmacotherapy of choice. AIMS: To investigate the efficacy and tolerability of escitalopram in the treatment of generalised social anxiety disorder. METHOD: Patients with generalised social anxiety disorder were randomised to receive placebo (n=177) or 10-20 mg escitalopram (n=181) in a 12-week, double-blind trial. The primary outcome measure was the mean change from baseline to last assessment in the Liebowitz Social Anxiety Scale (LSAS) total score. RESULTS: The study showed a statistically superior therapeutic effect for escitalopram compared with placebo on the LSAS total score (P=0.005). There were significantly more responders to treatment for escitalopram than for placebo (54% v. 39%; P<0.01). The clinical relevance of these findings was supported by significant reduction in the work and social components of the Sheehan Disability Scale and by the good tolerability of escitalopram treatment. CONCLUSIONS: Escitalopram was efficacious and well tolerated in the treatment of generalised social anxiety disorder.