The hydroconversion of abietic-type rosin acids, with a tri-ring structure into mono-ring structure hydrocarbons, was investigated. The reactions were performed at 380 degrees C under 7500 kPa of H-2 pressure over sulfided NiMo catalysts supported on alumina, USY-zeolite and mixed alumina/USY-zeolite. The NiMo supported catalysts were characterized using N-2-physisorption, ethylamine-temperature programmed desorption (ethylamine-TPD), scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM) and temperature programmed oxidation (TPO). The sulfided NiMo supported on only USY-zeolite showed the highest selectivity towards production of the mono-ring hydrocarbons such as methyl cyclopentane due to the strong Bronsted acid character of USY-zeolite. Whereas, the sulfided NiMo supported on alumina with weaker Bronsted acidity showed strong selectivity towards the di and tri-ring hydrocarbons such as dimethyl tetralins and retene. Moreover, the selectivities towards the mono-ring hydrocarbons over the NiMo catalysts with mixed supports were lower with a higher alumina content. Finally, the results show that the sulfided NiMo catalyst supported on alumina/USY-zeolite support with 50 wt% zeolite achieved a good level of deoxygenation, ring opening and cracking of the rosin acid while avoiding excessive coke formation.