This paper presents a study carried out to determine the threshold value of sense of equilibrium on sloping floors. The study consists of experiment and research carried out on inhabitants of boarding house with inclined floors. The main results of this study were as follows; 1. By the experiment, it was determined that about 60% of subjects perceived a change in slope of 1.5 degrees. 2. By the research, it was determined that about 50% suffered subjective symptoms from a change in slope of 1.6 degrees. 3. The periods of recovery from there symptoms were about 60 days up to a change in slope of 1.6 degrees. And in cases where the change in slop was greater than 1.6 degrees, the period of recovery was often greater than 1 year.