Traditionally, ice class rules and regulations for ships sailing in ice have been developed by nations whose fairways are blocked by ice in winter. Strengthening of ships for sailing in ice-covered waters has not been regulated by international treaties, but coastal states have imposed requirements for ships to be ice strengthened when entering their ports or sailing in their coastal waters. Recently, the International Maritime Organization (IMO) adopted new energy efficiency regulations for new ships, where the special needs of ice-strengthened ships have been taken into account. IMO has also developed a mandatory code for ships operating in polar waters. The code contains safety regulations, including ice strengthening, and regulations covering prevention of pollution of the Arctic and Antarctic marine environment by ships. It is evident that ships sailing in ice conditions require special consideration, especially when international regulations for protection of the environment from pollution by ships are developed. In this document, the most important ice class rules are described. The energy efficiency regulations of IMO and the development of the Polar Code are discussed briefly, with emphasis placed on how the special needs of ships designed to sail in ice conditions have been taken into account in IMO regulations.