Convention on the Settlement of Investment Disputes Between States and Nationals of Other States (Washington, 18 March 1965) has determined the international procedures for the settlement of such investment disputes and made the legal background for states to go out the practice of the implementation of their right on diplomatic protection of their persons. It enabled to convert possible international investment conflicts into private ones.In the article the author researches the conditions, which are necessary for International Centre for Settlement of Investment Disputes to have its jurisdiction. The general rule is that a written consent of parties is required for this purpose. It is dispensable that such consent should have the form of a written document signed by the parties. Other forms are possible (the exchange of letters, telex, telegrams or other means of telecommunications as well as the exchange of statements of a claim and defence in which the existence of an agreement is alleged by one party and not denied by another).The author considers some cases of the International Centre and concludes that it can also have jurisdiction over investment disputes, if a state stipulates appropriate provisions in treaties or national legislation. Simple reference is not sufficient. The provisions concerned should show clearly that the state has given its consent to the jurisdiction of the International Centre.