Two experiments were conducted to compare the nutritive value of dextrin to that of various carbohydrate sources and to determine the optimal incorporation ratio with lactose for pigs weaned at 21 days of age. In each experiment, eighty pigs (BW 6.43±0.18 kg in experiment 1 and 6.93±0.19 kg in 2) were used as an experimental unit and allotted to 20 groups (4 pigs/group, 5 groups/treatment) using a completely randomized block design. Each group was assigned to one of 5 dietary treatments. Dextrin (control), maize starch and 3 different sources of sugar (lactose, glucose, and sucrose) composed 5 dietary treatments for experiment 1. Five 5 graded lactose:glucose ratios (100:0, 75:25, 50:50, 25:75 and 0:100, diet A, B, C, D and E, respectively) were used as the treatments in experiment 2. In experiment 1, pigs fed the diet containing maize starch showed the lowest (P<0.05) average daily gain (ADG) and average daily feed intake (ADFI). During the second week, ADG improved (P<0.05) for the pigs fed diets containing dextrin and 3 different sources of sugar (lactose, glucose and sucrose) compared to pigs fed maize starch diets. For the third week after weaning, pigs fed diets with maize starch, lactose, glucose and sucrose had improved ADFI compared with pigs fed the dextrin diet (P<0.05). Overall, there were no significant differences in ADG and ADFI among treatments. However, pigs fed the dextrin diet had improved feed conversion ratio (FCR) compared with pigs fed other diets (P<0.05). During the initial 14 d postweaning (phase I), no significant differences were found in digestibilities of gross energy (GE), dry matter (DM), crude protein (CP) and crude ash (CA) among treatments. During the third week postweaning (phase II), the digestibilities of GE and CP of pigs fed the diet containing sucrose were higher than those of the other treatments. In experiment 2, overall, no significant differences were found in ADG, ADFI and FCR. During the initial 14 d postweaning (phase I), no significant differences were found in nutrient digestibilities except for gross energy (GE) digestibility. GE digestibility obtained from diet A was greater (P<0.05) than that from diet D, while those for diets B, C and E were intermediate.