Abstract This work was carried out to study effect substitution of corn grits with 5 % sweet potato or pumpkin grits for processing corn snacks using extrusion cooking techniques . The most favorable conditions for operator device were determined namely: feed moisture content , speed screw and extruder barrel temperature .Sensory evaluation such as color, taste, appearance, crispness and over all acceptability on the final product characteristics were studied. Three factors were identified for the operation as follows :feed moisture contents(16, 18 and 20%), screw speed(120, 140, 160rpm) and barrel temperature(130, 150 and 170 ° C) and the impact on the physicochemical properties such as bulk density (BD), expansion rate(ER) and water solubility index %( WSI %). The results indicated that the suitable expansion ratio were 2.01 and 2.62 gm/ cm3 and the swelling percentage were 3 .5 to3.4 %, respectively checks at 16% and 18% moisture for blend snacks1 ( 95% corn grits + 5% sweet potato grits )and blend snacks2 ( 95% corn grits + 5% pumpkin grits),while the proper screw speed ( 120 and 140 rpm ) by high barrel temperature ( 130 and 150 oc). The results showed significant differences in the color, taste, appearance, crispness and over all acceptability in each of the blend 1 and 2 as compared to the control (100% corn grits snacks) and had a best appearance of the blend 1 and the highest values ​​for color, taste and over all acceptability for the blend 2. So, it can be concluded that the process of extrusion device cooking heat the most suitable for operation is content feed humidity 16% ,temperature130 °c and the speed screw120rpm for a blend1 and 18% moisture ,150° c and 140rpmfor the blend 2to produce a product acceptable corn Snacks, and on the other the use of 5% of the sweet potatoes grits or pumpkin grits for the production of corn snacks contributed positively to show the desired qualities of a product such as increasing the expansion rate , improved crispness, taste and overall acceptability. This study highlights the importance of the selection experimentally the impact of new ingredients on different variables when manufacturing snacks from corn snacks. Keywords: Extrusion, Snacks, Screw Speed, Sweet Potato, Pumpkin, Corn grits and sensory.