In this study, compressive strength of concrete and the sulfate resistance of mortar containing waste ash that is palm oil fuel ash (POFA) collected from two different palm oil mills located in south and north Peninsular Malaysia and namely SPOFA and NPOFA are evaluated. The particle size of POFA was reduced to 45 ${mu}m$ by grinding it in Loss Angles machine. POFAs were used to partially replace 20% mass by mass of Portland cement Type I. The concretes were investigated and tested for compressive strength at ages of 7, 28 and 90 days using 100 mm cubes. To study the effects of sulfate attack on the blended mortars, $25 imes25 imes285$ mm mortar bars were prepared and cured according to ASTM C1012, and then immersed in 5% sodium sulfate $Na_2SO_4$ and magnesium sulfate $MgSO_4$ solutions for up to 15 weeks. SPOFA concrete shows higher compressive strength than ordinary Portland cement concrete (OPC). The resistance to sulfate attack of mortars containing SPOFA and NPOFA was substantially improved compared with OPC mortar.