Abstract: Objective To study the clinical efficacy and side effects of thalidomide in combination with dexamethasone,25 previously untreated patients with MM receiving the regimen were analyzed. Methods Thalidomide was given orally at an initial dose of 50 mg/d once per night,and then gradually increased to the maximum dose of 400 mg/d at a rate of 50 mg /d per week,according to individual tolerance.Dexamethasone was given at 40 mg/d either orally or intravenously on days 1～4,9～12 and days 17～20.Twenty-eight days a cycle, all patient s were t reated at least for 3 months. Results 　The overall efficacy of the 25 patient s involved in our research is 80 %, among which, 16 % achieved complete remission (CR) (4cases), 24 % achieved partial remission ( PR) (6cases), and 40 % had improvement, while 20 % had no effect (5cases) . The mainly side effect s include constipation, somnolence, edema etc. Conclusion 　The combination of thalidomide with dexamethasone was effective in patient s with newly diagnosed myeloma, with slight side effect s.