This paper deals with evaluation of the lower extremity efficiency and balance in rheumatoid arthritis (RA) patients. The authors' own test (LLFT-lower extremities functional test) and balance tests during normal standing and tandem positions with eyes opened or closed were used. Twelve patients with RA and fifteen controls for comparison were examined. Center feet of pressure dislocation on platform in normal standing with eyes open, normal standing with eyes closed, tandem left foot in front and tandem right foot in front positions and further dynamic balance tests on three different boards were analyzed. Visual Analogue Scale monitored the level of pain after each LLFT task. There was found a relation between the intensity of pain and overloading of joints in particular tasks, resulting in lower extremities dysfunction. A significant disbalance in medio-lateral direction during normal standing with eyes closed and tandem right foot in front positions and also in anterior-posterior direction in tandem right foot in front position during static balance tests was found. Correlations showed that patient's age, disease duration and Steinbrocker Functional Classes have an influence on parameters of balance tests. Results indicate that complex dysfunction of lower extremities causes disbalance of posture in static conditions.