Whenever the extirpation of intracranial tumors is planned, neurosurgeons always keep their eyes on the cerebrospinal fluid (CSF) space around intracranial tumors. If enough space exists in the neighborhood of the tumors, the damage to adjacent parenchyma may be reduced by the procedure through the CSF space. A newly advanced MRI pulse sequence: the FLAIR (fluid attenuated inversion recovery) imaging, in which a long TE spin echo sequence is used with suppression of the CSF with an inversion pulse, displays the CSF space as a no-signal intensity area. There have been only a few reports, however, on the FLAIR pulse sequence of brain tumors as yet. We examined 34 cases of intracranial tumors by FLAIR images and analyzed the advantages and disadvantages of the FLAIR pulse sequence for decision making on tumor removal. Making use of the FLAIR pulse sequence, the CSF space is depicted as a no-signal intensity area and much more information about perifocal edema and the invasion area around the tumors can be provided than that provided by the other ordinary pulse sequences (T1 weighted images, T2 weighted images and Proton weighted images). Therefore, operative strategies can be more easily worked out on the FLAIR images. Furthermore, the difference between arachnoid and epidermoid is able to be detected on the FLAIR images. Nevertheless, on FLAIR images, the tumors without perifocal edema or invasion to adjacent parenchyma were not apparent and the difference between tumoral dissemination into multi-ventricular space and the periventricular artifact of FLAIR images could not be distinguished. The FLAIR pulse sequence has other artifacts like intraventricular flow related enhancement and so on. If the images are carefully checked up on the above-mentioned points, the FLAIR pulse sequence of MRI can not fail to be useful in making plans for operations on intracranial neoplasms.