Magnetic resonance imaging (MRI) findings of knee pathologies were compared to arthroscopic findings. Prior to arthroscopic examination, magnetic resonance images were obtained in a series of 34 patients. The accuracy, specifity and sensitivity of MRI in the evaluation of medial meniscus, lateral meniscus and anterior cruciate ligament lesions were determined. MRI offers a high percentage of accurate diagnoses in lesions of these structures. There fore, it was concluded that MRI was an excellent substitute for diagnostic arthroscopy.