OBJECTIVE: To describe initial experience with resting-state correlation mapping as a potential aid for presurgical planning of brain tumor resection. METHODS: Resting-state blood oxygenation-dependent functional magnetic resonance imaging (fMRI) scans were acquired in 17 healthy young adults and 4 patients with brain tumors invading sensorimotor cortex. Conventional fMRI motor mapping (finger-tapping protocol) was also performed in the patients. Intraoperatively, motor hand area was mapped using cortical stimulation. RESULTS: Robust and consistent delineation of sensorimotor cortex was obtained using the resting-state blood oxygenation-dependent data. Resting-state functional mapping localized sensorimotor areas consistent with cortical stimulation mapping and in all patients performed as well as or better than task-based fMRI. CONCLUSION: Resting-state correlation mapping is a promising tool for reliable functional localization of eloquent cortex. This method compares well with "gold standard" cortical stimulation mapping and offers several advantages compared with conventional motor mapping fMRI. © 2009 by the Congress of Neurological Surgeons.