The paper examines the influence of the central bank’s monetary policy on trade credit financing in Poland. The aim is to establish the nature and scope of the private sector’s response to modifications in monetary policy. An additional issue is whether there is a substitution effect between bank credit and trade credit. Both these issues are subject to formal statistical analysis. In the process, the author takes a comprehensive look at the monetary policy stance of the Polish central bank. He proposes a simple and intuitive indicator in this area based on money supply and demand data. Using a regression analysis, Młodkowski finds a strong and statistically significant relationship between monetary policy and trade credit. His findings also confirm the existence of a substitution effect between bank credit and trade credit. The author builds two regression models, one for “trade credit extended” and the other for “trade credit used.” In the case of “trade credit used,” both the scope of the relationship and its significance are stronger than in the case of “trade credit extended,” Młodkowski says. This is due to an asymmetry of statistical data subject to analysis. Poland’s Central Statistical Office only gathers data from businesses with more than 45 employees. In another conclusion involving trade credit theories, Młodkowski proves wrong a financial aid theory that suggests that enterprise size is a factor that leads to an asymmetry in the propensity to extend and use trade credit. This theory does not hold true for Poland, Młodkowski says.