The main purpose of this article is to find out if there is a correlation between the announcement of the stock split and the market price. This analysis comprises 76 stock splits from Warsaw Stock Exchange which took place between 2011 and 2016. In this study the Market Model was used, and the deviations from the norm were shown as abnormal rates of return and cumulated abnormal rates of return. The differences of the rates of return are characterized by statistical significance.