OBJECTIVE To asses the efficacy of combination therapy of glibenclamide and Kelening in treating the non-insulin dependent diabetes mellitus (NIDDM). METHODS Sixty-five patients with NIDDM were randomly divided into two groups. One group was treated with both glibenclamide and Kelening, the other with glibenclamide alone. RESULTS After treatment for 12 weeks, the levels of fasting blood glucose (FBG), postprandial blood glucose (PBG) and HBAIC were reduced significantly in glibenclamide-Kelening group. In both groups, the degree dropped of the levels of FBG were almost the same, but the levels of PBG and HBAIC in glibenclamide-Kelening group were reduced more significantly than those in glibenclamide group, and the incidence of hyperinsulinemia had dropped considerably. CONCLUSIONS Glibenclamide in combination with Kelening in the treatment of NIDDM is more effective and less toxic, and the combination may reduce the dosage of glibenclamide in NIDDM.