The present study aimed to explore the phytochemistry and antidiabetic activity of Clematis buchananiana DC. A new compound (1) characterized as 3-[(11’’-hydroxy, 3’’,6’’,10’’,10’’- tetramethyldodecene)] 6-[(3’’’,4’’’,4’’’-trimethylhexene)] 5,7,2’,4’,6’pentahydroxy 8, 3’,5’ tri methyl flavanone was isolated from the aerial parts of the plant. The methanolic extract of the plant at a concentration of 1 mg/mL showed a 75.00% reduction in α-amylase and 73.13% in α- glucosidase enzyme activity. Moreover, the methanolic extract at 100 mg/kg b.w. showed a significant decline in blood glucose levels of alloxan-induced diabetic rats both in acute and chronic studies. The results were compared with glibenclamide, an oral hypoglycemic agent, which was used as a positive control. The present study concludes that the plant has substantial antidiabetic potential in diabetic rats. These results are indicative and further studies are needed to revalidate the findings.