PURPOSE: The purpose of this study is to evaluate the MR images of solitary cerebral metastasis and glioblastoma multiforme to determine the differential findings. MATERIALS AND METHODS: Ten cases of solitarycerebral metastasis and 14 cases of glioblastoma multiforme were retrospectively reviewed, all of which were proved by pathologically. The MR findings were compared in regard to tumor size and location, degree of edema, enhancement pattern, and shape of rim enhancement. RESULTS: Mean maximum diameter of solitary cerebral metastasis was 3.85cm(s.d. 1.47). Metastatic lesions were located in corticomedullary junction(70%) with cerebellum in 2cases. The locations of glioblastoma multiforme were white matter(64%) without cerebellar involvement and the mean maximum diameter was 5.43cm(s.d. 0.99). In solitary cerebral metastasis, the size of edema was larger than thetumor diameter in 50%, but glioblastoma multiforme did not show severe degree of edema. Rim enhancement seen in 7cases of solitary cerebral metastasis showed unilocular shape and complete rim in 6 cases, and even thickness and smooth inner margin in 5 cases. Howevere, rim enhancement seen in 11 cases of glioblastoma multiforme showed multilocular appearance with septa in all cases, incomplete rim in 5 cases, and uneven thickness and irregular inner margin in 10 cases. CONCLUSION: Tumor location, degree of edema, and rim enhancement pattern on Gd-enhanced MR may be useful in differentiation between solitary cerebral metastasis and glioblastoma multiforme.