The purpose of this study was to evaluate the accuracy of sonography in measuring the dimensions of the cadaveric patellar tendon to determine whether sonography might have future applications in the preoperative assessment of autograft tissues before anterior cruciate ligament (ACL) reconstruction. Eleven lower-extremity human cadaveric limbs, with an average donor age of 75 years (range, 67 to 87 years), underwent patellar sonography with a 7.5-MHz transducer. Patellar tendon thickness, width, and length were measured sonographically. After skin removal, the patellar tendon dimensions were measured manually. Sonographic and manual measurements were compared statistically. Sonographic and manual measurements showed good agreement for thickness. There was poor agreement for width and length. Because of its limited accuracy, sonography cannot be recommended for the measurement of the patellar tendon before ACL reconstruction.