Vacuum residue (VR) is potential to be used as a feedstock for mesophase pitch (MP) production because of its low cost and aromatic content. MP, which is a liquid-crystalline state of VR, may be used as precursor of activated carbon (AC). Gum rosin containing conjugated double bonds may be added to and can improve crystallinity and pore surface area in further processes of carbonisation and activation. In the present study, co-pyrolysis was carried out in a stirred tank reactor at 450°C with holding time for 120 minutes. The amount of gum rosin mixed with VR was varied 0, 5, 10 and 15% wt of VR. The precursor products had C/H mole ratio of about 2.43, 2.37, 2.28, and 2.01 by increasing gum rosin added. Subsequently, this precursor underwent carbonization at 700°C with holding time for 120 minutes under N2 flow and activation. KOH solution was used as activating agent to the precursor of activated carbon. Activated carbon gave higher surface area and lower C/H atom ratio with increasing gum rosin added during co-pyrolysis. With gum rosin addition, surface areas of ACs were 120.81, 194.56, 312.36, dan 462.19 m2/g, respectively, and crystallite sizes increased from 8 to 22 Å.