Background : Since dysthymia begins in late childhood or adolescence and has a chronic course, long-term pharmacotherapy may be required. New generation antidepressant, moclobemide, with more acceptable side effect profiles, is effective in the treatment of dysthymia. The main objective of this study was to determine whether they exhibit comparable efficacy and tolerability in dysthymia to amitriptyline. Method and Materials : The efficacy and tolerability of the moclobemide and amitriptyline, were compared in a eight-week single-centre double-blind study in patients(n=37) with dysthymia using he HAMD-17, the Clinical Global Impression Scale(CGI), the Montgomery-Asberg Depression Rating Scale (MADRS), Efficacy Index-Therapeutic Index(EITE), 4-point Index Side Effect Scale(4-PISES), and Efficacy Index- Side Effect Scale(EISE). Results : A total of 37 patients entered the study, 19 were randomly assigned to the moclobemide group and 18 to be amitriptyline group. Demo-graphic and illness characteristics were similar in both groups. There were no significant difference between two groups at the total 17-HDRS score, the HAMD-17% improvement, the total MADRS score, CGI response, and the EITE. In the comparison of EISE between two groups, the scores of the moclobemide group were relatively lower than the amitriptylinen group in full treatment. And the differences were significant(moclobemide group $1.39{pm}0.61$ ; amitriptyline group $2.00{pm}0.85$, p<.001). At the 4-PISE, There was no serious or treatment threatening side effects. And there was no specific difference in side effects between two groups. The moclobemide group reported higher EIR scores than the amitriptyline group at every follow up day, but the differences were not significant. And, there was no significant differences in the scores of five HRQOL subcategories which is compared between two groups at every follow up days. Conclusions : In terms of 17-HDRS and MADRS, moclobemide and amitriptyline are equally effective at least in allevating dysthymic symptoms. But moclobemide tended to be less troubling and better tolerated than amitriptyline. Therefore, moclobemide treatment can be used as a safe, and higher satisfactory treatment strategy for the dysthymia.