Purpose: To review MR findings of the posterior fossa hemangioblastomas and to evaluate diagnostic value of MRI correlated with CT and angiographic findings. Materials and Methods: The MR findings in twelve patients with surgically proven posterior fossa hemangioblastomas including one case of von Hippel- Lindau disease were retrospectively analyzed and correlated with CT (7 patients) and angiographic findings (9 patients). Results: On MRI, five hemangioblastomas were located in the cerebellar hemisphere and seven in the vermis. The masses appeared to be solid in 3 cases(25%), solid tumors with central cyst in 2 cases(17%), and cyst with mural nodules in 7cases(58%). Abnormal tumor vessels represented by characteristic signal voids on MRI were observed in 9 cases(75%) and were not seen in 3 cases(25%) with mural nodule below 1.5 cm in diameter. On pre-contrast CT, hemangioblastomas appeared poorly marginated slightly hyperdense masses in solid tumors, and hypodense cystic masses in cysts. After contrast enhancement, solid tumors were markedly enhanced, but it was difficult to differentiate hemangioblastomas from other tumors. In nine patients, angiograms demonstrated hypervascular blush corresponding to the solid component of the tumors. Conclusion: MRI was superior to CT in evaluating the characteristic of abnormal tumor vessels and mural nodules, delineation of tumor margin and tumor extent. Angiography was useful in the diagnosis of cystic hemangioblastomas which contain small mural nodule (less than1.5 cm in diameter) without definite vascular signal voids on MRI. MRI demonstrated solid or cystic tumor with small mural nodule and abnormal vascular signal voids in the posterior fossa should suggest hemangioblastoma.