Objective: To test the ex vivo mechanical properties of canine patella-ligament-tibia (PLT) segment and establish the relationship between donor size and PLT dimensions to the mechanical properties of PLT grafts. Study Design: Ex vivo mechanical testing study. Sample Population: Canine PLT segments (n=21 dogs; 42 PLT). Methods: Morphometric measurements of PLT segments were taken from computed tomography (CT) images and compared with results obtained using calipers. PLT were tested to failure at a rate of 100%length/s. Mechanical properties and failure mode were recorded. Results: PLT width and thickness (P<.001 for both) measured by calipers were significantly lower than those taken from CT images. Thirty-five (83%) specimens failed by avulsion fracture from the patella, 1 failed mid-ligament, and 6 failed by tibial fracture. Dog weight and PLT length had the strongest Pearson's r value when correlated with load at failure (r=0.73, 0.81, respectively). Conclusion: Dog weight and PLT length were the best predictors of load at failure. PLT failure load of dogs weighing >25kg were similar to those reported for the cranial cruciate ligament (CCL) suggesting that the PLT may be a suitable allograft for CCL replacement.