BACKGROUND: Social anxiety disorder (SAD) is associated with substantial reduction in health-related quality of life (HRQoL). Escitalopram has proven efficacy in the short-term treatment of SAD and prevention of relapse. OBJECTIVES: To determine whether the clinical effects of treatment translated into HRQoL benefits and to investigate costs of SAD treatment. METHODS: Data on HRQoL and resource utilisation were collected in a previously published clinical trial of escitalopram in relapse prevention. Among 517 patients, 371 responded to 12 weeks of open-label treatment with escitalopram and were randomised to escitalopram or placebo for 24 weeks. HRQoL was assessed using the short form (SF)-36 instrument and SF-6D utilities (preference-based index scores for overall HRQoL) were calculated. Costs were calculated for responders over the acute phase and for non-relapsed patients over the continuation phase, applying UK unit costs. RESULTS: Health-related quality of life was significantly improved after the acute phase when compared with baseline. The SF-6D utility increased by 0.047 in responders (p < 0.0001) and 0.021 in non-responders (p = 0.0005). Healthcare costs were non-significantly lower in acute phase than during prestudy phase (p = 0.0587 from NHS perspective), as were productivity costs (p = 0.1440). HRQoL at last visit was lower in relapsed than non-relapsed patients. The difference in utility was -0.026 (p = 0.0007). Healthcare and productivity costs were non-significantly lower in the escitalopram group than in the placebo group. CONCLUSIONS: Both effective acute treatment of SAD and prevention of relapse with escitalopram are associated with significant HRQoL benefits. Despite some limitations, the cost analysis suggests that savings in physician-visits and inpatient care may offset drug acquisition costs.