The concept of liability of public authority based on the principle of equity was introduced into the Polish law under the article 5 of the Act of 15 November 1956, “On the Liability of the State for Damage Caused by State Agents” . The regulation of article 5 of the Act was transposed into the Civil Code of 1964 without major modifications. It covered liability of the state and local self-government units for damage inflicted by a tort of a functionary (article 419 of the Civil Code). By the amendment to the Civil Code of 2004, article 419 of the Civil Code was abolished and the new article 4172 of the Civil Code, which provides liability for lawful exercise of public authority based on considerations of equity, was introduced. Article 4172 of the Civil Code provides that if by lawful exercise of public authority an injury to the person was caused, the injured person is entitled to obtain a full or partial compensation as well as monetary compensation for moral losses, when it is evident from the circumstances of the case, especially from victim’s incapacity to work or his/her poor financial situation that compensation is required by the considerations of equity. The amendment to the Civil Code of 2004 has brought about essential changes in the regime of state liability. Under the present law, the decisive factor of liability is the character of the conduct that results in the damage. The domain of special state liability is limited to torts committed in the exercise of public powers. For its private economic activities the state is liable according to the general rules of civil law. This change - in comparison to the former regulations of liability of public authority based on principle of equity - is unfavourable for the injured party, especially as regards damage sustained in medical practice, as medical care of patients, in general, is not considered to belong to the sphere of public administration.