Despite major advances in our knowledge of glycemic pathophysiology and the availability of multiple therapeutic options to confront type 2 diabetes, unraveling the complex link between genetic risk and environmental factors in this burgeoning epidemic has proven difficult. Linkage approaches have clarified the etiology of monogenic diabetic syndromes and congenital lipodystrophies, and candidate gene association studies have identified a number of common variants implicated in type 2 diabetes. This year we have witnessed the advent of genome-wide association scanning: As many as nine genetic loci have now been reproducibly associated with type 2 diabetes in five genome-wide scans. Of particular interest are preliminary explorations of the connections between genetic risk and pharmacologic response. An improved understanding of genetic mechanisms should allow us to test whether behavioral or pharmacologic therapies can be tailored and thus the tremendous disease burden inflicted by type 2 diabetes alleviated.