The knee joint is often subjected to high loads, which can lead to injury and osteoarthritis. To better understand its behaviour, a finite element model of the joint was created. A hyperelastic material model was created to represent articular cartilage. A six parameter Ogden curve was fiitted against experimental stress-stretch data of cartilage. This material was applied to two different finite element models of the knee created from anatomical slice images. The complete models were validated against data from experiments performed on whole knees. Under compressive loading, the deflection of the model joints were found to be within one-half of a standard deviation of the experimental data. One model was tested in alternate configurations; its response was found to be strongly related to cartilage thickness and knee flexion. Therefore, it is concluded that this cartilage material model can be used to accurately predict the load response of knees.