The article identifies the provisions in the Polish income tax acts that are potentially incompatible with the Internal Market freedoms. Specifically, the author discusses the methods of interpreting the fundamental freedoms, identifies the methodology for distinguishing provisions that are potentially incompatible with the EC Treaty, compiles a list of the Polish direct tax provisions that are potentially incompatible with the EC Treaty and considers the procedural remedies in the Polish legal system that can be relied on by taxpayers subject to tax in breach of EC law.