Androstenone, skatole and indole are main compounds responsible for boar taint, an off-odour in meat of some entire male pigs. Several feed ingredients derived from chicory have been reported to reduce fat skatole levels, while results for indole are more contradictory. The skatole-reducing effect is probably based on the prebiotic effects described for fructan compounds. Inulin and oligofructose have a high and low degree of polymerization, respectively. The fermentation rate decreases with an increasing degree of polymerization, which may result in differing effects of the compounds on skatole and/or indole levels. In this study we evaluated the effect of the inclusion of 5% inulin or 5% oligofructose during the last 3 weeks before slaughter on carcass quality, concentration of skatole and indole in back fat as well as on the olfactory evaluation of boar taint in fat. Carcass weight did not differ between treatment groups but lean meat percentage increased when feeding oligofructose (P = 0.019) compared to the control group, which is relevant for further research. Inclusion of 5% inulin or 5% oligofructose in the finisher diet of entire male pigs significantly reduced the back fat skatole concentration, without influence on indole. Olfactory score for boar taint tended to decrease when oligofructose was added to the diet.