We have performed 65 arthrographies of the knee since May, 1976, and 38 cases out of them showing normal finding through clinical and radiologic evaluation as well as postoperative confirmation were studied for normal variation. The result were as follows: 1. Variation in size and shape of the menisci including notching or step-like pattern along their free margins were seen in 18 cases, and 13 cases of which were occurred in the lateral meniscus and the remainder 5 cases in the medial meniscus. 2. Contrast delineation in the buras surrounding popliteus tendon were 13 cases, which is simulating lateral detachment of the lateral meniscus. 3. Tears or detachments were simulated by synovial folds projecting toward each menisci or intercondyloid fossa in 12 cases. 4. Technical errors causing difficulty in interpretating fine detail of the arthrograms were found in 4 cases with delayed procedure or incomplete empting of joint fluid, and in 2 cases by extraarticular injection of con rast medium.