The invention relates to a process for converting oxygenated organic material, to olefins using small pore molecular sieve catalysts. More particularly, the invention relates to a method for converting oxygenated organic material to olefins with improved the olefin yields and decreased yields of methane and other light saturate byproducts. The improved yield slate is achieved by treating the small pore molecular sieve catalyst with a modifier selected from the group consisting of polynuclear aromatic heterocyclic compounds with at least three interconnected ring structures having at least one nitrogen atom as a ring substituent, each ring structure having at least five ring members, decomposed derivatives of said polynuclear aromatic heterocyclic compound, and mixtures thereof.