We investigated variations in biomass among oil palm progenies and quantified K and Mg uptake by assessing the distribution pattern of these minerals throughout plant organs, including roots and bunches. A split-plot trial was set up in which potassium chloride (KCl: 60% K2O) and kieserite (MgSO4: 27% MgO) were applied as main factors, each with three levels: 0, 1.5, 3.0 kg KCl palm˗1 year˗1; and 0, 0.75, 1.5 kg MgSO4 palm˗1 year˗1. Each fertiliser combination was applied to subplots containing four oil palm progenies (C1 to C4). Samples of oil palm organs were collected to assess their dry matter (DM) and mineral contents. Oil palm biomass was significantly different among progenies, with C3 having the highest biomass (268 kg DM palm˗1). K and Mg contents in the entire palm also varied among progenies. C2 and C3 progenies exhibited the highest amounts of K (3.81 and 3.86 kg K palm˗1, respectively), whereas C1 and C4 displayed 3.35 and 3.31 kg K palm˗1, respectively. However, C4 progeny showed the highest leaflet K concentration, revealing the dilution phenomenon and the inequal mineral distribution among palm organs. Progeny C3 had the highest Mg content (0.54 kg palm˗1) and was the most productive, exporting more K and Mg through harvest than other progenies. Our results indicate genetic variability in K and Mg uptake by oil palm, and planting materials with high K and Mg uptake efficiency would be valuable for farmers and breeders.