SUMMARY Tensile strength of normal cranial cruciate ligaments in dogs was determined with a tensile-testing machine. A procedure to measure the cross-sectional area of cranial cruciate ligament was devised. Mean length of the cranial cruciate ligament was 0.8 cm. Fracture stress and percentage of elongation were determined for each ligament. Percentage of elongation varied between 40.0% and 77.6%, and tensile strength, between 176.0 and 447.0 kg./sq. cm. These values differed significantly (P < 0.005) among dogs. There was no significant difference between left and right ligaments of the same dog.