This study shows that pre-treatment of empty fruit bunches (EFB) has a positive impact on the energy content of syngas from the gasification process. In Malaysia, there is an estimated 25 million tonnes of EFB which can be used for power generation or for producing value added products through gasification. Gasification is a thermochemical process where the oxidant (air) is lower than the stoichiometric requirement, thus producing volatile syngas such as carbon monoxide, methane, hydrogen that contribute to the energy content. However, EFB has relatively higher ash and alkali metal content compared to other types of biomass, such as wood. Alkali metal contents such as potassium and sodium (K and Na) have been reported to reduce the initiation temperature for the formation of slag and clinker, and can cause operational issues for gasification systems, though other results show that alkali metals increase the gasification reactivity. Pre-treatment of the EFB may be required for reducing alkali metal related operational issues, and increase the performance of gasification in terms of the energy content of the syngas. Thus, this study investigates the effect of pre-treatment on the properties of the EFB, with a focus on the alkali metal content. The correlation between the pre-treatment (and the alkali metal content) on the yield and composition of the syngas from the gasification process is investigated. © Published under licence by IOP Publishing Ltd.