Hallux valgus is a common condition that may lead to considerable pain and disability. There is also evidence that hallux valgus may impair balance and increase the risk of falling in older people. Although a number of plantar pressure studies have been undertaken in people with and without hallux valgus, little is known about how hallux valgus affects basic gait patterns or the movement of the upper body when walking. Measurements of temporospatial parameters of gait and acceleration patterns of the head and pelvis were obtained in 71 people (24 men, 47 women) between 75 and 93 (mean 80 +/- 4) years of age when walking on both a level surface and a specially designed irregular walkway. Foot problems, vision, peripheral sensation, strength, and reaction time also were evaluated. After adjusting for potential confounders, subjects with moderate to severe hallux valgus were found to exhibit significantly reduced velocity and step length on both walking surfaces and less rhythmic acceleration patterns in the vertical plane when walking on the irregular surface compared to subjects with no or mild hallux valgus. These findings indicate that hallux valgus has a significant detrimental impact on gait patterns that may contribute to instability and risk of falling in older people, particularly when walking on irregular terrain.