A preferred embodiment of a system for loading catalyst and/or additives into a fluidized catalytic cracking unit includes a bin for storing at least one of the catalyst and/or additives, and a loading unit in fluid communication with the storage bin and the fluidized catalytic cracking unit on a selective basis. The loading unit is capable of being evacuated so that a resulting vacuum within the loading unit draws the catalyst and/or additive from the bin. The loading unit is also capable of being pressurized so that the catalyst and/or additive is transferred from the loading unit to the fluidized catalytic cracking unit.