Fourteen magnetic resonance (MR) images of 11 patients with cerebral sparganosis were reviewed retrospectively and compared with 13 computed tomographic (CT) scans of 10 of the patients. All patients underwent both nonenhanced and contrast material-enhanced MR imaging. All white matter degenerations, which were slightly hypointense on T1-weighted images and were hyperintense on T2-weighted images, were seen as areas of low attenuation on CT scans. Better contrast between normal and degenerated brain tissues was seen at MR, and two lesions were seen that were missed at CT. The parasitic granuloma was isointense to brain parenchyma on images obtained with all pulse sequences. On two follow-up MR images, location or shape of the enhancing lesions changed, suggesting migration of the worm. A new finding of hyperintensity on T1-weighted images and hypointensity on T2-weighted images in subcortical areas probably due to petechial hemorrhages was demonstrated in eight patients only at MR. Small calcific foci, which were important diagnostic clues of cerebral sparganosis, were detected in four patients only at MR, while they were seen in eight patients at CT.