The concurrent evolution of resid fluid catalytic cracking (RFCC) processes and catalyst technology over the years is discussed. Resid FCC catalysts today are designed making use of the following features : (a) High activity, selectivity and metals resistant zeolites; (b) Highly accessible catalyst architecture for optimal site utilization, bottoms cracking, Conradson carbon residue (CCR) conversion and easy stripping; and (c) Specially designed metal-support interaction systems to reduce the detrimental effects of metal contaminants. The future will require even more robust RFCC catalyst systems. These catalyst systems should be very accessible and effective in cracking large hydrocarbon molecules and should have the capability to handle contaminants such as metal-, sulfur-, and nitrogen-compounds. Conversion of CCR to non-coke components will be crucial in order to reduce the delta coke and hence improve the processability of heavier resids. Processability here is meant not only in terms of coke and heat balance considerations, but also involves avoiding fouling of the unit hardware by unconverted heavy hydrocarbons and coke precursors. Last, but not the least, present and future catalyst technology must be formulated and adapted to the specific commercial process unit needs and constraints, thus leading to the most cost effective solution for the refiner.