Banana and lentil flour blends were processed in a single screw extruder modifying the flour properties of the blend (20.5-79.5%), at selected range of die temperature (145-175 ºC) and the feeding moisture content (20-24%).Functional characteristics evaluated in the extrudates were water absorption index (WAI), water solubility index (WSI), bulk density (BD), paste viscosity properties, microstructure and resistant starch content. The concentration of lentil/banana blends and temperature were the most important variables affecting dependent variables WAI, WSI, BD and viscosity properties. The results of this study indicated that extrusion cooking induced desirable functional characteristics to lentil/banana blends by increasing their resistant starch content.