MRI is of increasing importance as a noninvasive method for the investigation of abnormalities in the knee. 2-D spin-echo sequences were compared with 3-D gradient-echo sequence using normal and cadaver knee joints. 3-D imaging using a fast computer was found to provide significantly improved diagnostic information concerning the cartilage when compared with a 2-D spin-echo techniques. The important advantages are: sections of less than 1 mm., reconstruction in any required plane, which can be related to the complex anatomy of the knee joint, and very good distinction between intra-articular fluid, fibrocartilage and hyaline cartilage.