Several studies show that sucrose does not aggravate hyperglycemia in type II diabetes mellitus, but sucrose is still restricted in dietary recommendations. Since sucrose in high carbohydrate diets elevates fasting triglyceride levels, the effects of sucrose were evaluated in diets with fixed carbohydrate levels. Eighteen diabetic volunteers receiving no medication were given weight maintenance diets with 50 percent carbohydrate, 35 percent fat, 15 percent protein, and 120 g of sucrose for 10 days as inpatients. They were then randomly assigned diets of similar composition with either 220 g of sucrose (high sucrose diet) or less than 3 g of sucrose daily (complex carbohydrate [CHO] diet) for one additional month. There were no differences in fasting, one-, two-, and three-hour post-lunch serum glucose levels; 24-hour glycosuria; glycohemoglobin levels; fasting and postprandial serum triglyceride levels, or fasting high-density lipoprotein-cholesterol levels. Twelve patients with preexisting higher triglyceridemia had similar trends, but the postprandial triglyceride levels were lower in the high sucrose diet group of this subset (p less than 0.05 in the third week). Postprandial serum insulin levels declined in the second week on the complex CHO diet. More than 75-fold difference in sucrose intake with constant carbohydrate and fat did not affect glycemic or triglyceridemic control in type II diabetic patients. The reported high sucrose-carbohydrate-induced rise in fasting triglyceridemia was not present when a diet high in sucrose was given without changing total carbohydrate.