Difructose anhydride (DFA) III acts on intestinal epithelial tight junctions and promotes calcium absorption through the paracellular pathway in dairy cows. This trial was done to investigate the effects of DFA III supplementation on passive IgG transfer and serum IgG concentration in calves. Twenty-four newborn Holstein male calves were grouped as 12 pairs, with each pair receiving a separate batch of pooled colostrum (PC) from the first 2 milkings. One calf from each pair was allocated to the treatment group (n = 12) and received 18 g of DFA III in each feeding; the other calf was assigned to the control group (n = 12) and did not receive DFA III. All calves were fed 2 L of PC per feeding at 1, 10, and 24 h after birth. Prefeeding blood samples taken at 0 h, 10 h, 24 h, 36 h, 4 d, and 7 d were analyzed for serum IgG concentration. Apparent efficiency of IgG absorption in the treatment group was higher compared to that in the control group. Serum IgG concentration of calves in the treatment group was higher for all sampling time points except for 0 h of age. Mean serum IgG concentrations in the treatment and control groups at 36 h of age were 22.3 and 17.7 g/L, respectively. Serum IgG concentration at 36 h of age was positively related with the IgG concentration in the PC in both groups, and it was higher in the treatment group than in the control group at the same IgG concentration in the PC. These results indicate that absorption of ingested IgG by endocytosis as well as a nonselected concentration gradient process of the paracellular pathway of the intestinal epithelium could be enhanced by DFA III supplementation. Supplementation of DFA III in PC containing various IgG concentrations could improve IgG absorption as well as calf serum IgG concentration.