The effect of pore structure on the gasification of two chars impregnated with potassium carbonate catalyst is investigated. Well-characterized char samples were reacted with carbon dioxide, water vapor, and oxygen. The effects of catalyst on the magnitude of the gasification rate as well as on the entire rate vs. conversion pattern are reported. Reactivity and structural data are analyzed to obtain a meaningful comparison of the gasification behavior for all char-gas pairs. Initial intraparticle catalyst dispersion was strongly influenced by the pore structure of the chars. During gasification with carbon dioxide and water, the catalyst appeared to redistribute itself in accordance to the accepted reaction mechanism, leading to superior catalytic activity. The reported measurements indicate that both the pore structure of the chars and the chemistry of a particular reaction are key factors in determining the overall catalytic performance.