Several associating factors including unfit footwear problems cause hallux valgus. We think that the disease is also associated with walking posture and muscle strength as major factors. The aim of the study is to investigate and report the walking posture, the muscle strength in the lower limbs and the pass way of center of pressure on foot sole in patients with hallux valgus in order to develop the study of hallux valgus in future. Three patients with hallux valgus and two healthy subjects participated in the study. Both patients had bilateral hallux valgus, and the degree of deformities between the right and left toe were different. Three measurements were performed: 1. the movements of the trunk and pelvis during walking using three dimensional motion measurements systems; 2. the center of foot pressure (COP) during walking by force plate; 3. the maximum muscle strength for hip and knee joints muscle groups utilizing a hand held dynamometer. The association among three variables (the movements of the trunk and pelvis, COP, and muscle strength) were analyzed. The muscle strength in patients with hallux valgus was shown to be weaker than that in healthy subjects. About three degrees difference in pelvic tilt angle in the frontal plane during stance phase was observed between the right and left side for all subjects. Further, on the side in which hip abductor strength was weaker, the pelvic tilt angle was shown to be smaller and the COP moved on the lateral side of the sole of the foot for all subjects. About five degrees difference in pelvic rotation angle in the transverse plane during stance phase was also found between the right and left side. On the side in which hip flexor strength was weaker, the pelvic rotation was shown to be larger, and the COP moved through the medial side of the sole of the foot. These results suggest that weakness of hip abductor and flexor may be associated with increasing of stress on the sole of the foot.