A series of observation covered four patients with hemangioblastomas of the posterior cranial fossa. The study analyzed the infomative value of CT, MRI (with and without contrast enhancement), vertebral angiography, MR angiography and perfusion CT in the diagnosis and differential diagnosis of hemangioblastomas of the posterior cranial fossa and tumors of another origin. Perfusion CT study (estimation of the relative cerebral blood volume) has indicated that hemangioblastomas in relation to the medulla is an increased perfusion area. The analysis of complex radiological study in patients with hemangioblastomas of the posterior cranial fossa has demonstrated that perfusion CT may be useful in differentiating hemangioblastomas from other contrasted neoplasms. Moreover, perfusion CT provides additional information on tumor hemodynamic changes.