In recent years, the requirement of sustainability has given rise to application of high volume industrial waste in the production of building materials. Fly ash has been found to perform satisfactorily in this regard, and this development is expected to continue in the years ahead because of technological, economical and ecological advantages of the material. This study focuses the potentials of high volume palm oil fuel ash (HVPOFA) replacement of ordinary Portland cement (OPC) and presents experimental results on the effect of sulphate attack. Concrete cube specimens containing 50, 60 and 70% POFA were made alongside with mortar bars made of the same material composition were immersed in 10% magnesium sulphate (MgSO₄) solution. Mass and strength loss of concrete cube as well as expansion of mortar bars were studied using wet and drying circle method. The results obtained and observations made were compared with those of 100% OPC specimens. It has been found that the expansion and mass loss significantly decreased with the increase in POFA content, which clearly demonstrates that the replacement of cement with high volume POFA is advantageous particularly in aggressive sulphate environment.