The empty fruit bunch (EFB) is a cumbersome biomass generated during the palm oil milling process. It is one of the most extensively researched biomass. This is due to its abundant availability from the palm oil industry – spread over Malaysia, Indonesia and to some extent Thailand. It is widely recognised as a potential fuel but its use faces much hurdle, mainly due to its high ash content. Converting EFB into valuable fuel resources such as bio-oil and bio-char, through the pyrolysis process, would be beneficial not only to support national energy security but also economic growth. In this study, the thermal conversion of the unwashed and washed EFB through fast pyrolysis was carried out using a fluidised bed reactor at 500°C with particle sizes ranging from <90 μm to 180 μm. Three types of pre-treatment were performed. These were washing with H₂SO₄ (0.1 M), NaOH (0.1 M), and distilled water. The aims were to investigate the impact of the different washings on the resulting pyrolysis products and the corresponding ash effects. The results indicated that the EFB washed with H₂SO₄, which gave the highest reduction in ash content i.e. ~56%, gave the maximum bio-oil yield (55.6 wt.%) while that washed using NaOH with ~50% ash increment produced the highest amount of bio-char (36.9 wt.%) and gas (38.8 wt.%). The resulting bio-oil and bio-char from the washed feedstock with much reduced ash had similar fuel characteristics with those from the unwashed feedstock, with the latter a better fuel in terms of calorific value, i.e. 19 -23 MJ kg^-1 vs. 20-25 MJ kg^-1, respectively.