PURPOSE: To assess the efficiency of functional magnetic resonance imaging (fMRI) in demonstrating motor-sensorial cortical areas in mass lesions neighboring the perirolandic area and investigating its pre-operative sensitivity. MATERIALS AND METHODS: In the study, 20 right-handed patients with different types of intraxial and extraaxial mass lesions in or neighboring the perirolandic area were used. Of the all lesions, 6 were diagnosed as metastatic masses, 2 as oligodendroglioma, 2 as astrocytoma, 5 as glioblastoma multiforme, 2 as meningioma, 2 as arteriovenous malformations and 1 as porencephalic cyst. The study was performed on a 1.5 T unit. Images were acquired at the axial plane using T1 weighted spin echo, T2 weighted fast spin echo and fast FLAIR. Functional imaging was performed by blood-oxygen-level-dependent (BOLD) technique and single-shot gradient echo-planar sequence (SSEPI). During the sequence period a total of 420 images were acquired, each of which had 10 slices. By matching the resource functional images with T1 and T2 weighted anatomical images, the functional anatomy of the brain has been mapped. Sensorial-motor cortex has been activated by the finger-tapping-paradigm. RESULTS: Two patients could not included in the study because of extensive movement artifacts and meaningless BOLD answers. Eighteen of the patients had significant BOLD answers in bilateral peri-central sulcal area and in the center of the supplementary area. Activation areas were obtained neighboring the mass lesions and edema surrounding the lesion. CONCLUSION: fMRI can demonstrate motor-sensorial cortex in situations in which the anatomical order of perirolandic area has been changed by mass lesions. fMRI shows high sensitivity in the evaluation of lesions neighboring the perirolandic area preoperatively. Therefore fMRI can provide important information in patient selection, detection of different surgical choices and planning the surgical intervention.