Polymeric blends based on polycarbonate (PC) and acrylonitrile-styrenebutadiene copolymer (ABS) are applied mainly in the electronic and automotive industries. Studies to improve the properties of PC/ABS blend have led to graphene nanoplates (GNP) addition, a carbon nanofiller derived from graphite that presents some of the promising properties of graphene. In this work, the effect of the addition of GNP (3 and 5 wt%) and maleic anhydride grafted ABS (ABS-g-MAH) were evaluated on the thermal, mechanical, rheological, and electromagnetic properties of PC/ABS blends (85/15), a different blend ratio of previous studies. It was verified that the GNP addition significantly increased the thermal stability of the blends. Furthermore, the mechanical tests showed that ABS-g-MAH acted as an efficient compatibilizer for the PC/ABS blends, and the GNP addition improved the Shore D hardness, the elastic modulus, and the maximum tensile strength of all compositions.Besides, it was observed an overlapping effect of the GNP and ABS-g-MAH addition on the mechanical properties of the blend. The addition of 3 wt% GNP to the PC/ABS (85/15) blend also doubled the elongation at break of the material. Furthermore, these contents resulted in a slight increase of the electromagnetic waves attenuation of 1-2 dB associated to electromagnetic waves reflection.