A method for hydrocracking a feedstream comprising liquid hydrocarbon by forming a dispersion comprising hydrogen-containing gas bubbles dispersed in the liquid hydrocarbon, wherein the bubbles have a mean diameter of less than about 5 μm, and introducing the dispersion into a hydrocracker comprising hydrocracking catalyst. A method for hydrocracking by subjecting a fluid mixture comprising hydrogen-containing gas and liquid hydrocarbons to a shear rate greater than 20,000 s−1 to produce a dispersion of hydrogen in a continuous phase of the liquid hydrocarbons, and introducing the dispersion into a fixed bed hydrocracking reactor from which a hydrocracked product is removed. A system for hydrocracking a hydrocarbonaceous feedstream including at least one high shear device capable of producing a tip speed of the at least one rotor of greater than 5.0 m/s, and a hydrocracker containing hydrocracking catalyst and comprising an inlet fluidly connected to an outlet of the high shear device.