The article investigates the price behavior of Warsaw Stock Exchange-listed companies that carried out initial public offerings (IPOs) between 2004 and 2009. The authors focus on the determinants of the process and on the relationship between a company’s size and profitability, on the one hand, and its aftermarket price performance, on the other. The authors aim to answer three questions: first, whether or not Polish IPOs exhibited short-term underpricing and long-term underperformance during the studied period; second, whether such a trend was “distinct for the size and profitability subsamples;” and, third, whether “profitability in the size subsamples changed from before to after going public.” The authors say they recorded a lower level of underpricing and underperformance than in previous studies focusing on the Warsaw Stock Exchange. They add that “the pre-issue company size influences the IPO underpricing with a higher level of returns for smaller companies.” In terms of long-term performance, “the opposite relation between size and buy-and-hold abnormal returns was found.” Lizińska and Czapiewski also found that “the higher the pre-issue profitability, the higher the underpricing.” The authors conclude that the profitability of large companies in the pre-IPO period tends to improve to a greater extent than the profitability of small companies. At the same time, large companies tend to experience a less dramatic drop in profitability after the flotation than small companies.