Abstract: Objective: To observe the effect and side-effect of low-dose thalidomide in treatment for myelodysplastic syndromes(MDS).Methods: Twelve cases of low-risk MDS(RA/RARS) and 9 cases of high-risk MDS(RAEB) were treated by combined therapy of thalidomide,androgen and retinoic acid.Results: The total response rate was 47.6%.In the low-risk MDS group,hematological improvement(HI) was observed in 6 cases,with an effective rate of 50.0%;in the high-risk MDS group,complete remission(CR) was achieved in 1 case,partial remission(PR) in 1 case and hematological improvement(HI) in 4 cases.There was no significant difference between the two groups(P>0.05).Eight of the 21 patients receiving thalidomide achieved HI(6 HI-E,4 HI-P and 3 HI-N),no side effects were found.Conclusions: Low-dose thalidomide has positive effect on MDS with little side effect,and the effect is more obvious on the patients who rely on red blood cell transfusion.Thalidomide is the first choice of single or combination drug for patients with MDS.