To determine the glucose responses of diabetes mellitus type II subjects to fruits, four locally available fruits (containing 25 g of available carbohydrates per serving portion) of chico, mango, pineapple, and papaya were tested among ten type II diabetic subjects, using wheat bread as the control. Results of the in vivo test indicated that chico and mango had significantly lower (P ≤ 0.05) blood glucose areas compared to wheat bread. Chico and mango also had a much lower glycemic index (GI), 57 and 59, respectively, compared to pineapple, 73 and papaya, 86. Differences in glucose responses to fruits and their varying GI are attributed to the amount of fiber, type and amount of sugars found, presence of antinutrients, acidity and physical characteristics of the fruits when chewed. The high fiber content of chico (7.9%), its fructose content (5.3%), its grainy texture when chewed and the presence of antinutrients (saponin, sapotin and achrasaponin) may contribute to its slow digestion and absorption. The low GI and blood glucose response of mango may be because of its fructose content (3.0%), acidity content (malic, citric and tartaric) and its phytic acid content (0.03%). Furthermore, starch, which is a possible factor contributing to low GI, is present in chico (0.8%) and mango (0.3%). Pineapple and papaya, the test fruits that elicited higher blood glucose responses and GI, have much lower fiber contents, less acids and contain glucose and sucrose sugars.