The statements made so far about internal sources of labour law focus on Art. 9 of the Labour Code. Meanwhile, this provision applies only to a fraction of legal acts adopted in work establishments. Especially since in many cases law-making entities are not even aware that they are introducing a normative act. This last remark applies especially to the so-called company policies or activities performed by trade union bodies during a strike. In the history of Polish labour law, there has never been such a detailed identification of the sources of internal law. An additional advantage of the study is the fact that it touches on the virtually unexplored subject of legal acts adopted by corporations in relation to national organizations, which is practically unexplored in Poland. Thus, a work was created that has no equivalent in Polish legal literature.