For many years, mainly to simplify data analysis, scientists assumed that during a gait, the lower limbsmoved symmetrically. However, even a cursory survey of the more recent literature reveals that the human walkis symmetrical only in some aspects. That is why the presence of asymmetry should be considered in all studiesof locomotion. The gait data were collected using the 3D motion analysis system Vicon. The inclusion criteriaallowed the researchers to analyze a very homogenous group, which consisted of 54 subjects (27 women and 27men). Every selected participant moved at a similar velocity: approximately 1,55 m/s. The analysis includedkinematic parameters defining spatio-temporal structure of locomotion, as well as angular changes of the mainjoints of the lower extremities (ankle, knee and hip) in the sagittal plane. The values of those variables werecalculated separately for the left and for the right leg in women and men. This approach allowed us to determinethe size of the differences, and was the basis for assessing gait asymmetry using a relative asymmetry index,which was constructed by the authors. Analysis of the results demonstrates no differences in the temporal andphasic variables of movements of the right and left lower limb. However, different profiles of angular changes inthe sagittal plane were observed, measured bilaterally for the ankle joint.