The purpose of this study was to determine the three-dimensional kinematics of the knee joint during running on level surfaces and surfaces of different degrees of camber. Fifteen college-age students (eight males, seven females) having no previous history of knee injury were subjects. A triaxial elgon was used to measure the movement of each subject's right and left knees when running on a horizontal or laterally inclined treadmill at 2.4 m·s−1during each experimental condition (on the horizontal surface and on cambers of +0.087, +0.174, −0.087, and −0.174 radians). There was a significant difference (P< 0.05) between +0.174 and −0.174 rad camber mean values for all six dependent variables (i.e., support and swing, flexion-extension, internal and external rotation, and valgus-varus range of motion). There was also a significant difference (P< 0.05) when +0.174 and −0.174 rad camber were compared to 0 rad camber during both the support and swing phases of flexion-extension. Surface camber mean values for +0.087 and −0.087 rad were significantly different (P< 0.05) during the swing phase for internal and external rotation. This study showed that the kinematics of the knee joint are significantly altered when running on a laterally inclined surface.