The purpose of intraoperative monitoring of many modalities is to save some structures of the nervous system being at risk of damaging during surgical procedures. In cerebellopontine angle (cpa) tumour cases these nervous system structures can include cranial nerves (trigeminal, facial, cochlear, accessory), motor and sensory tracts localised within brainstem, and other. Continuous registration of somatosensory and auditory evoked potentials as well as electromyography of masseter muscle, orbicular muscle of eye and trapezius muscle during procedure is the method of brainstem, cochlear tract and cranial nerves status evaluation. Direct stimulation of cranial nerves within posterior fossa using bipolar electrode is the method of facial, trigeminal and accessory nerves localisation, especially in patients with large tumours. In Department of Neurosurgery Silesian University School of Medicine for intraoperative monitoring of many modalities in cpa lesion cases Nocolet Viking IV D unit with special IOM software is employed. Authors presented own experience in such method and effect in treatment of group of 15 patients operated with electrophysiological intraoperative monitoring.