Title: Testing of the postural stabilization in relation to weight changes of breasts Objectives: Aim of this study is to assess postural changes after breast reduction. To capture the level of postural stability before and after surgery and to evaluate changes between these states. Methods: This thesis is a clinical trial of one group of persons (n=12). It has been created as a quasi experiment. For testing there was used diagnostic method of postural somatooscilography (PSOG) which includes performing postural provocation test on the platform Posturomed under standard conditions. The testing was performed three times. The measurement was recorded by program Microswing 6.0, the collected data was evaluated by program Posturomed Commander and further analyzed by one - way Analysis of Variance in statistical program OpenStat. Results: Managed to prove, that breast reduction has a positive influence on postural stabilization at women suffering from gigantomastia. Status of postural stability was significantly improved two months after surgery. Keywords: postural stability, Posturomed, postural somatooscilography, gigantomastia, reduction mammaplasty