The representation of capital companies in the activities concluded with members of the management board is an extremely important and practically significant issue. In the literature we can find a number of opposing views regarding the effects of violation of the principles expressed in art. 210 and 379 Commercial and Company Code. The issue of dispute here is the possibility of confirming actions carried out in violation of the standards referred to. This issue is even more relevant due to the fact that in 2018 the provisions of the Civil Code were amended in this respect. The article attempts to determine the impact of the amendment to art. 39 Civil Code on the principles of representing a capital company in contracts and disputes between the company and its members of the management board.