Research on foot orthotics is primarily restricted to their effect on the lower limb during running. Research is limited, however, on the potential of foot orthotics to control the mechanics of the foot during walking. The purpose of this study was to examine the interactive effect of foot orthotics and two walking speeds on the angular changes at the rearfoot, ankle, and knee, and temporal events during stance. Ten subjects demonstrating a minimum of 3 degrees of calcaneal eversion in relaxed standing participated in the project. All subjects routinely wore functional orthotics that were used during testing in conjunction with personal athletic shoes. Individuals were tested with and without the orthotics while walking on a treadmill at 2 and 3 mph. A four-camera motion analysis system was used to capture three-dimensional motion at 60 frames per second. Angle plots illustrated changes in joint motion at the knee, ankle, and rearfoot. Temporal data for heel strike, heel rise, and toe off of the foot during the stance were calculated. A two-factor repeated analysis of variance was used to determine the main and interactive effects of the orthotic and speed on the dependent variables. When walking with the orthotic, there was a significant reduction in the degree of pronation throughout stance as well as an increase in the duration of stance time as measured from heel strike to heel rise. The orthotic did not significantly reduce the velocity of pronation during the first 20% of stance. There was a speed effect for peak dorsiflexion and knee flexion.(ABSTRACT TRUNCATED AT 250 WORDS)