Acrylonitrile butadiene styrene (ABS) terpolymer is a low-cost engineering thermoplastic that can be easily processed. However, its insulation property restricts its use in electronic applications. The addition of conductive filler can transform the ABS into conductive polymer composite. The recycled carbon black (rCB) powder that is extracted from the waste tyres can be a potent conductive filler for polymer composite. This research focused on producing more effective rCB filler as a reinforcing material in an ABS terpolymer. Acid functionalization was done to improve the compatibility of the rCB with the ABS and facilitate its dispersion throughout the ABS matrix. The modified rCB filler; the so-called “acid functionalized recycled carbon black (f-rCB)” was employed to produce ABS/f-rCB with improved mechanical and electrical properties. The effects of rCB and f-rCB loadings (0, 5, 10, 15, 20 and 25 wt. %) on the tensile and electrical properties of the ABS composite were studied. Results indicated that the 10 and 15 wt. % of f-rCB filler has greater capability to reinforce and enhance the electrical conductivity of the ABS as compared to the rCB filler due to improved compatibility between filler and matrix, thus forming homogeneous composite when used at optimum loading.