In this study buckwheat flour was used as a supplement of a commercial gluten-free formulation (MLECZNA and NISKOBIAŁKOWA). The effect of 30 or 50% substitution of formulation basis with buckwheat flour on the technological and rheological properties of dough was observed. The dough was analysed for contents of proteins, elements and resistant starch. Viscoelastic properties of the examined dough were measured using Rheostress 1 (ThermoHaake) in an oscillation mode. Changes in the viscoelastic properties were expressed as elastic modulus (G’) and viscous modulus (G”). The substitution of 30 or 50% of the gluten-free formulation basis with buckwheat flour increased the level of total proteins, macro- and microelements, as total mineral components, and resistant starch. Irrespective of the level of buckwheat flour in gluten-free formulations a decreasing water binding capacity was confirmed. Dynamic rheological studies of gluten-free dough of MLECZNA formulation showed the higher elastic (G’) and viscous (G”) moduli in comparison with NISKOBIAŁKOWA formulation. Both analysed moduli decreased when buckwheat flour replaced a part of the analysed commercial gluten-free formulations. It indicated that the buckwheat flour could diminish the structural function of compounds substituting for gluten in gluten-free formulations. Based on the results obtained it could be concluded that buckwheat flour is a promising valuable supplement of gluten-free formulations.