The article deals with the institution of mistake in the proposal of the General Part of the new Civil Code. The author represents in general a positive opinion regarding the proposal, as it is very well-considered and innovative. However, the purpose of this paper is to formulate some short, critical remarks about disadvantages of certain proposed legal solutions. The analysis mainly deals with the prerequisites of mistake, inter alia with the requirement of causal connection between the mistake and the conclusion of the contract. According to the draft, it is not always necessary that the other party knows or should be expected to know that the concerned facts are essential for the counterparty. This presupposition is, thought, false from both theoretical and practical point of view, what is most apparent in cases concerning common mistake. Moreover, proposed repeal of the law dealing with the issue of the fraud is very contentious. That change could make it hard to deter the other parties from engaging in immoral, fraudulent activities, and consequently it may seriously harm innocent parties. In author's opinion, it would be also proper in some cases to shorten the period during which the mistaken party can avoid the contract or to implement a solution that could otherwise reduce this period.