It is well recognized that content and composition of dietary fibre (DF: non-starch polysaccharides (NSP) and lignin) have a profound influence on nutrient digestibility and utilization in poultry as it represents the part of the feed that cannot be digested by endogenous enzymes. DF are influencing the digestibility and utilization of nutrients because of its indigestibility, encapsulation of important nutrients in cell walls and because of its influence on viscosity in the gastrointestinal lumen caused by soluble NSP. Knowing the content and composition of the DF fraction is therefore crucial for obtaining high efficiency. This may be even more important in the future as poultry diets are expected to be based on a larger proportion of DF rich co-products than in the past. Common for the DF rich feedstuffs is that they have a higher and more variable content of DF and consequently lower nutrient digestibility and utilization. Exogenous carbohydrases can be used to overcome some of the negative effects of DF but since the nutritional effects of DF and the effects of carbohydrases are related to its composition it is important with analytical data on these aspects. Analyses of DF are usually done using enzymatic-chemical-gravimetric procedures which provide detailed information on the DF fraction. The latter requires tedious and costly wet chemical methods. Near-infrared reflectance (NIR) spectroscopy, which utilises the interaction between light and matter, however, holds the potential to be used as a tool for measuring content and composition of DF.