The article determines the functions of the notariat in Ukraine, Poland and Lithuania, their differences and common features, to establish additional functions of the notary, to study the procedure for performing the notarial function and its purpose. It was determined that the function common to all mentioned above notariats is to ensure non-dispute in civil legal relations through official notarization of acts, that the legislation of all three countries provides for the duties of a notary in the field of prevention of money laundering and terrorist financing and control over the payment of necessary taxes and fees in cases specified by law. It was established that in all legal systems notaries, along with the notarial function, can be mediators, but with their own characteristics. It was determined what functions are inherent to notariat of Ukraine, in contrast to the notariats of Poland and Lithuania. It was established that the national legislation of each country determines which acts are subject to mandatory notarization, but at the same time, in all the mentioned countries, if the participants in a civil relationship wish to regulate their relations, they can do so in a notarial manner, if this does not contradict the requirements of the law.