The aim of this work was to assess the influence of including two different sources of non-starch polysaccharides (NSP): insoluble NSP (iNSP) like wheat bran (WB) and/or soluble NSP (sNSP) like sugar beet pulp (SBP) on the nutrient digestibility and the physicochemical characteristics of the hindgut digesta, and on the microbial population and the fermentation end-products. A total of 32 piglets (7.4 ± 0.76 kg of body weight (BW)) were distributed into four experimental diets: a control diet (CT), or diets with 8% WB, 6% SBP, or 4% WB and 3% SBP (WB–SBP). Two experimental periods were considered (0–10 and 10–15 days after weaning) during which BW and voluntary feed intake were measured. Four animals per treatment were euthanized on days 10 and 15. Colon digesta was sampled and analyzed for organic matter digestibility (OMd) and starch digestibility, unbound water, water retention capacity (WRC) and short-chain fatty acids (SCFA). At the same time, enterobacteria and lactobacilli loads were determined in caecum digesta. The presence of iNSP in the diet (WB and WB–SBP diets) diminished the unbound water of colonic digesta in the two experimental periods (P=0.01 on day 10 and P