This study was conducted to compare the effects of four types of dietary fiber supplementations (cellulose, pectin, guar gum, and polydextrose) on gastrointestinal function, diabetic symptom amelioration and lipid & glucose metabolism in streptozotocin-induced diabetic rats. Six groups of male rats were fed ad libitum dietary fiber-free control diet or one of experimental diets containing 5% dietary fiber for four weeks. All types of dietary fiber supplementation seemed to protect the diabetic animals from the loss of body weight. The primary diabetic symptoms such as polydipsia, polyphasia, polyuria and urinary glucose excretion were ameliorated by cellulose, pectin, and guar gum, but not by polydextrose. Gastrointestinal transit time was significantly shortened and fecal dry weight was significantly increased in all the dietary fiber-supplemented groups except the polydextrose group. Large intestine was significantly lengthened by dietary fiber feeding. The serum triglyceride and total cholesterol levels were effectively lowered by pectin, guar gum and polydextrose. Regardless of their types, the fiber supplementation had no effect on serum HDL-cholesterol. Whereas fasting blood glucose level was significantly lowered by all types of fiber supplementations, glucose tolerance was more effectively improved by pectin and guar gum.