Deep eutectic solvents (DESs) have received considerable attention in recent years due to their low cost, low toxicity, and biodegradable properties. In this study, a sequential pretreatment comprising of a DES (choline chloride: urea in a ratio of 1: 2) and divalent inorganic salt (CuCl2) was evaluated, with the aim of recovering xylose from oil palm fronds (OPF). At a solid-to-liquid ratio of 1: 10 (w/v), DES alone was ineffective in promoting xylose extraction from OPF. However, a combination of DES (120 degrees C, 4 h) and 0.4 mol/L of CuCl2 (120 degrees C, 30 min) resulted in a pretreatment hydrolysate containing 14.76 g/L of xylose, remarkably yielding 25% more xylose than the CuCl2-only pretreatment (11.87 g/L). Characterization studies such as FE-SEM, BET, XRD, and FTIR confirmed the delignification of OPF when DES was implemented. Thus, the use of this integrated pretreatment system enabled xylose recoveries which were comparable with other traditional pretreatments.