An open, baseline controlled study of sertraline in depressed patients was conducted in 6 treatment sites. Eighty-two patients between 20-82 years of age with DSM III-R diagnosis of a depressive illness received sertraline 50-200 mg/day. Among evaluable patients, there was a significant reduction in depressive symptoms at the final visit. A statistically significant change from baseline in Montgomery Asberg Depression Rating Scale (MADRS), Hospital Anxiety Depression Rating Scale (HAD), and Clinical Global Impression Severity of Illness Scale (CGI-S) scores was demonstrated. On the basis of MADRS criterion, 96.0 per cent of patients responded and on the basis of CGI-S criterion, 86.6 per cent of patients responded. In 73.2 per cent of patients the final sertraline dosage was 50 mg. All-cause adverse events were recorded in 35 patients (42.7%), whereas 22 (26.8%) had adverse events that were judged treatment-related. The most frequently reported events were nausea and headache. Overall, the patients tolerated sertraline very well. The results of the study suggest that sertraline is an effective, well-tolerated and safe treatment for depression in Thai patients.