This study analyzed tibio-femoral joint kinematics and contact area during knee flexion at 0°, 30°, 60°, 90° and 135° using magnetic resonance imaging with a 3D-fat-suppressed fast low angle shot sequence (3D-FLASH). At a 200N loading situation, knee flexion angles were chosen to be 0°, 30°and 60°. Sagittal and coronal images were obtained under the loading and unloading situations from 6 healthy male Japanese volunteers. At unloading situation, from 0° to 90° the centroids of the medial and lateral contact areas translated backward and outside. From 90° to 135° the centroids of the medial and lateral contact areas translated backward and inside. The contact areas tended to decrease, but from 60° to 135° knee flexion the medial contact area was not changed generally. At loading situation, almost the same results as observed at unloading situation for each translation were obtained. However, the translation of centroids of the medial and lateral contact areas decreased with an increase of knee flexion, and the centroids moved roughly straight backward as well. The contact areas increased at each knee flexion angle as compared to unloading situation. These results showed good correlation with previous ones found in the other studies of knee kinematics.