MRI-based oxygenation mapping would be beneficial for treatment planning of high-grade gliomas. We used dynamic contrast-enhanced imaging and a combined quantitative susceptibility mapping and blood oxygenation level-dependent approach to quantify the oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO2) in 6 patients with glioblastoma multiforme and 2 with anaplastic astrocytoma. Robust reconstruction of physiologically meaningful uniform OEF maps in healthy tissue was achieved and OEF was significantly lower in the tumor compared to the contralateral side. Blood flow was significantly higher in the tumor only for glioblastoma multiforme. CMRO2 showed no significant differences.