The classification of hyperlipoproteinemia observed in twenty-three noninsulin dependent type II diabetic patients who were not controlled well by diet and sulfonylurea was carried out. Four groups were classified (group 1, normal VLDL and normal LDL; group 2, high VLDL and normal LDL; group 3, high VLDL and high LDL; group 4, normal VLDL and high LDL). The most usual hyperlipoproteinemia group was group 3 and the frequency was about 56 %. The relationship between abnormality of serum lipoprotein and some factors such as insulin secretion, hemoglobin A1c concentration, lipoprotein lipase activity was studied among three groups (group 1, group 2, group 3). However, it seemed that there was no significant relationship between hyperlipoproteinemia and these factors. The significant difference of relative body weight was observed between group 1 and group 3. This result suggests that there is a significant relationship between hyperlipoproteinemia (high VLDL and high LDL) and obesity observed in type II diabetes mellitus. The reason why obesity caused hyperlipoproteinemia was not cleared, but it seemed that a difference of insulin secretion did not refer to hyperlipoproteinemia observed in type II diabetes mellitus with obesity, because there was no significant difference of insulin secretion between group 1 and group 3.