The morphological changes of blends of nylon-6 and acrylonitrile-butadiene -styrene (ABS) with reactive compatibilizer [poly (N-phenylmaleimide-styrene-maleic anhydride)] as a function of viscosity ratio of the components, concentration of compatibilizer, and the feed rate have been studied using an intermeshing corotating twin screw extruder. The occurrence of reaction between the amine end group of nylon-6 and maleic anhydride of compatibilizer during melt blending was identified by the solvent extraction and infrared spectroscopy study. It was found that the minimum dispersed phase size occurred at the viscosity ratio (p) = 0.75. Dispersed phase size was decreased significantly by the addition of compatibilizer and tended to equilibrate at about 15 wt % compatibilizer based on the amount of nylon-6. It was observed that the morphology was strongly dependent on the feed rate. The presence of maximum dispersed phase size was observed as a function of feed rate.