The influence of full-fat soy flour (FFSF) 0-27.0 g/100 g, water content 31.0-35.0 g/100 g and extrusion conditions on the cooking and color characteristics of spaghetti was investigated. The process was performed with a speed of 10-40 rpm and a water circulating temperature of 35-70 degrees C. The results showed that adding FFSF causes decreases (P< or =0.05) in cooking time, cooking weight, intensity and hue characteristics. However, the cooking loss and saturation of spaghetti increased (P< or =0.05). The temperature and speed of the extruder had no significant effect on the cooking and color attributes. Interaction between them and the components, however, had a slight synergistic effect on characteristics. Also, interaction between the components and the water temperature has a negative effect on the color and cooking loss. Data analysis showed that the cooking and color characteristics were optimized when 56.9 g/100 g wheat flour, 12.1 g/100 g FFSF and 31.0 g/100 g water content at a screw speed of 40 rpm and a temperature of 35 degrees C were applied.