Data correlations are presented for equilibrium adsorption of pure hydrocarbon vapors and their mixtures. The systems represented are C1 to C4 hydrocarbons (olefins and paraffins) on gas-adsorbent grades of activated charcoal. The mixture data are limited to binary and ternary gas systems. The adsorption conditions represented among the correlated data cover ranges of 77° to 175°F. temperature and 0 to 100 lb./sq. in. gauge. With the use of empirical adsorption constants, a common correlation of specific adsorption capacity for the various hydrocarbons is presented; it applies for either pure components or their mixtures. A correlation is given also for adsorption relative volatilities. Approximate adsorption heats, a limited amount of high-temperature steam adsorption data, and sample calculations on applications of the correlations are included. The prediction methods are recommended for adsorption conditions up to 250°F. and 250 lb/sq. in. gauge for the particular systems studied.