PURPOSE: The purpose of this study was to evaluate the MR findings of benign and malignant musculoskeletal adipose tumors and to determine the points of difference between these two types. MATERIALS AND METHODS: This study involved 41 histopathologically proven cases; 26 were benign lipoma and 15 were liposarcoma. T1- and T2-weighted images were obtained in all cases and enhancement study was performed in 15 case of benign lipoma and14 of liposarcoma. To determine MR findings and possible differences between the two groups, we retrospectively analyzed size, location, margin, degree of signal intensity, homogeneity, enhancement pattern and internal septa, as seen on MR images. RESULTS: On both T1- and T2-weighted images, all lipomas showed a signal intensity similar to that of subcutaneous fat. Twenty-one lipomas had thin and regular internal septa and three showed focal enhancement. On T1-weighted images, 13 of 15 liposarcomas showed linear strands or patchy or diffuse areas with high signal intensity, representing a fatty component. Ten liposarcomas showed inhomogeneous signal intensity and the other five, homogeneous intensity. Irregular and thick septa were seen in nine liposarcomas, and in 12 cases, nodular diffuse enhancement was documented. CONCLUSION: Homogeneity of signal intensity, enhancing pattern and internal septa might be useful MR findings for the differential diagnosis of benign lipoma and liposarcoma.