PURPOSE: The purpose of present study was to determine effects of circuit class training (CCT) on the synthesis of central serotonin in people with post-stroke depression. METHODS: Forty patients with mild post-stroke depression were participated in current study. All subjects were assigned to two groups of CCT (circuit class training) group and SW (stretching and weight shifting) group. Both groups were performed for 80 minutes. The change of blood f-Trp, BCAAs, f-Trp/BCAAs and serotonin according to period training time were examined and the following results were obtained. RESULTS: In the CCT group, f-Trp, BCAAs, and f-Trp/BCAAs increased according to the time point. However, after 24 hour of circuit class training, all of these were significantly decreased by those before training. The change in blood levels of serotonin was the highest in immediately after the training in the CCT group while it was not changed significantly in the SW group. CONCLUSION: It can be seen that CCT can change the serotonin level and have an effect on the synthesis of central serotonin in people with post-stroke depression.