Morphology on the 75/25 polyamide 6 (PA6)/polycarbonate (PC) blends with various ratios of maleic anhydride functionalized poly[ styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS-gMA) to poly[styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS) was investigated by transmission electron microscopy, differential scanning calorimetry and small angle X-ray scattering. The total amount of added SEBS-gMA and SEES was held constant at 20 parts hundred resin, (phr) i.e. 20 g against 100 g of the total amount of PA6 and PC). The 75/25 PA/PC blend with 0/20 SEBS-gMA/SEBS showed a co-continuous phase structure. The co-continuous phase morphology is one of the hallmarks of spinodal decomposition (SD), which takes place in the partially miscible system. It has been known that a binary blend of PA6/PC is completely immiscible at all temperatures, In contrast, the 75/25 PA/PC blends with 5/15, 10/10 and 20/0 SEBS-gMA/SEBS showed dispersed PC macrodomains and SEBS/SEBS-gMA microdomains in the PA6 matrix, indicating that these blends are totally immiscible. On blending with 0/20 SEBS-gMA/SEBS, the PA6 crystallinity and crystallization temperature (T-c) were lower than in other blends and the periodic regularity of SEBS-gMA/SEBS microphase separation was higher. In the other blends, the crystallinity and T-c was high and the periodic regularity of SEBS-gMA/SEBS microphase separation was low. This behavior is believed to arise from the different phase morphology formed on changing the ratio of SEBS-gMA to SEES.