The results of measurements of selected physical, textural and quality characteristics of extruded snacks with addition of thermal-pressure modified starches are presented in the paper. Corn starch and potato starch were modified with twin-screw extrusion-cooking under the temperature of treatment 140oC at 25% of starch initial moisture level. Snacks with addition of 5, 10 and 15% of these modified starches were prepared with single screw TS-45 food extruder at two different configurations: type L/D=16:1 to process corn snacks (at 120 rpm) and type L/D = 18:1 to process potato pellets (at 80 rpm) for further deep oil frying snacks. In these corn snacks and potato fried snacks it was evaluated the expansion ratio, bulk density, cutting force during Warner-Bratzler knife cutting test, hardness during double compression test in Kramer cell, and sensory characteristics (appearance, shape, colour, taste, flavor and crispness) in 5-points scale. Increased level of modified starches in the recipe of extruded snacks influenced on higher expansion and lower bulk density of both tested products. Modified starches increased hardness of corn snacks and fried potato snacks and also lowered sensory properties of ready-to-eat snacks.