Standing balance was studied with use of a force platform (AMTI) in 67 subjects with classical/definite rheumatoid arthritis (RA) and 152 healthy subjects, 67 of whom formed a group matched for sex and age. Compared with healthy subjects, RA subjects showed significantly (p less than 0.01) greater postural sway, reflected by increased area and length of sway path, differences being greatest in those tests representing a relatively high level of difficulty, involving standing on one leg, looking straight ahead.