Non-insulin-dependent diabetes mellitus of early onset has recently been described in Caucasians as a distinct syndrome with a characteristic pedigree suggestive of inheritance of genetic determinants from both parents. It is characterized by absence of islet cell antibodies and the severity of its clinical course. We report a Chinese family pedigree of three generations in which this form of diabetes has affected the third generation. Some members of this pedigree had severe complications at presentation in their twenties.