The aim of this study was to determine if fat absorption is better after pylorus-preserving pancreatoduodenectomy (PPPD) or duodenum-preserving pancreatic head resection (DPPHR) compared with that following pancreatoduodenectomy with gastrectomy (SPD), provided the patients have similar pancreatic exocrine function. Fat absorption was studied using the 13C-trioctanoin breath test in patients who were grouped according to the degree of fibrosis of the pancreatic remnant. The latter was judged by histologically measuring the fibrosis in a transectional wedge of resected pancreas. We evaluated 11 SPD cases, 25 PPPD cases, and 9 DPPHR cases. The 13C excretion rates and cumulative excretion values following DPPHR or PPPD were significantly better than those following SPD. The 13C excretion rates and cumulative values for the patients with > 30% fibrosis of the pancreas were lower than those in patients with < 30% pancreatic fibrosis, regardless of the surgical procedure. The cumulative value in the SPD group, however, was lower than that in the PPPD or DPPHR patients with < 30% pancreatic fibrosis. The results suggested that fat absorption following PPPD or DPPHR is superior to that after SPD in patients with the same fibrotic area of the pancreatic remnant and depends on the degree of fibrosis in the pancreatic remnant.