The effect of ash removal pre-treatment of lignocellulosic biomass prior to catalytic pyrolysis for producing biofuels was investigated. Non-catalytic and catalytic pyrolysis of demineralized and raw biomass was performed in Py-GC/MS and bench-scale experiments to study the performance of in-bed and ex-bed upgrading. Pre-treated biomass shows a significant increase in the organic liquid yield in experiments performed at 600 degrees C: from 31 to 42 wt% compared to raw biomass, as well as a significant reduction of char yield. The performance of inbed catalytic pyrolysis of pre-treated biomass over HZSM-5 is limited compared to the corresponding raw material. However, ex-bed catalytic pyrolysis of pre-treated biomass at 600 degrees C results in an overall increased yield of BTX compounds. Pyrolysis vapors from pre-treated biomass present a suitable composition for catalytic upgrading after secondary vapor-phase reactions. Additionally, demineralization reduces the total acid number of derived liquids in catalytic and non-catalytic pyrolysis.