Recent advances in diagnostic modalities such as computerized tomography(CT-scan), magnetic resonance imaging(MRI), and electrophysiological examination including EEG, SEP, ABR, have facilitated the diagnosis of relatively small brain tumors, while refinement in microsurgical techniques with the aid of intraoperative echo-sonography, endoscopy, navigation surgery and application of intraoperative monitoring of brain function, have facilitated precise diagnosis and safe surgery for brain tumors. This paper presents the preoperative, intraoperative, and postoperative usefulness of these modalities in treating brain tumors.