The objective of the study was to compare the glycaemic index and glycaemic load of biscuits made with 100 % wheat flour type 650 and with two 100 % oat flours: commercial oat flour and residual oat flour (obtained after the production of fibre preparation). The biscuits were organoleptically assessed by a panel of assessors. The hardness of the biscuits was analyzed using a TA XT Plus Texture Analyzer along with penetration and intersection tests. AOAC methods were applied to determine the moisture and the content of the following components in the biscuits: total protein, crude fat, mineral compounds in the form of total ash, total dietary fibre including soluble and insoluble fractions, and β-D-glucans. The content of available carbohydrates in the biscuits was calculated according to the FAO/WHO recommendations. The food energy provided by the biscuits was calculated based on a method recommended by FAO that included the composition of the biscuits and the Atwater energy equivalents. The determination of the glycaemic index was carried out in a group of 15 volunteers using a method recommended by ISO 26642:2010. The organoleptic characteristics of both the wheat and the oat biscuits were assessed as very good; however, the biscuits made with oat flours (residual and commercial) were characterized by a better crispness. Replacing wheat flour with oat flours to make the biscuits caused the content of crude fat, total ash, dietary fibre (soluble and insoluble fractions) including β-glucan in those biscuits to increase statistically significantly. All the biscuits tested were characterized by a low glycemic index ranging from 46 to 50 and a low glycemic load, less than 10, and this resulted, mainly, from a small content of digestible carbohydrates (57 – 61 %) and a high content of fat (19 – 24 %) in those products.