Market forces and environmental legislation are increasing demand for hydrogen in oil refineries, while simultaneously restricting traditional hydrogen sources such as catalytic reforming. Effective recovery and efficient use of hydrogen are necessary if refiners are to maintain feedstock and product flexibility while avoiding unnecessary capital expenditure. A methodology for assessment of hydrogen resources is developed by analogy with the problem of process heat recovery. The effectiveness of hydrogen use is related to the cost of hydrogen recovery and the value added in hydrogen-consuming processes. The costs of hydrogen recovery by pressure-swing adsorption and membrane permeation are described, The value added in hydrogen-consuming processes and the availability of hydrogen are determined by the process chemistry and the prevailing economic conditions. A graphical display of the availability and distribution of hydrogen resources provides insight into refinery design and operations that supplements the information available from optimization by linear programming.