OBJECTIVE We report and discuss the imaging features of 8 cases of spontaneous unilateral adrenal hematomas, a rare lesion. METHODS Computerized tomography (CT) was done in 8 cases, magnetic resonance imaging (MRI) in 5, and CT and MRI in 5. Imaging findings were reviewed and correlated with histological findings in all 8 cases. RESULTS MRI was the most accurate imaging modality and showed variable appearances. On pathological evaluation the hematomas were old and organized. No contrast enhancement was noted on CT or MRI. CONCLUSIONS One must not consider the diagnosis of spontaneous adrenal hematoma only as superimposed on a phechromocytoma or malignant lesion in the case of an incidentally discovered large adrenal mass with normal biological findings. MRI signs of adrenal hemorrhage and the failure of enhancement of such a mass should strongly suggest adrenal hematoma.