Ileal and faecal excretion of the non-cellulosic components of the dietary fibre was studied in cannulated pigs fed wheat (control) and two inbred lines of rye with low and high (3.8% and 5.6%) level of soluble dietary fiber (SDF). As compared to the intake, the major fiber components arabinose and xylose were excreted in the ileal digesta in 81.9 and 81.8% after feeding with low-SDF rye and in 79.3 and 79.5% when wheat was fed to the animals. Significantly lower fiber degradation was observed after feeding pigs with high-SDF rye; the recovered arabinose and xylose amounted to 93.3 and 90.6%. It was also found that in the small intestine both sugars disappeared to the similar extent. Unlike in the ileal digesta, in faeces the lowest excretion of arabinose and xylose was observed after feeding pigs with high SDF rye (44.0 and 22.7%), the highest when wheat was fed (52.3 and 32.1%) and intermediate for low-SDF rye (49.2% and 28.3%). Whatever the diet, xylose was disappearing in a higher proportion than arabinose. Glucose absorption in the small intestine was notably influenced by the diets; more was found in the digesta after feeding ryes (14.5 and 11.2%) than wheat (6.6% of the intake). This can be explained by different viscosity of the cereals. It was estimated that glucose recovered in the digesta originated in about 69% from starch. Only trace amounts of glucose were found in faeces.