The article studies provisions of the Vietnamese law on cases where the State is required to appoint defense counsels to protect the legitimate rights and interests of the accused persons in the case settlement process when the accused persons, their representatives or kindred do not seek the assistance of defense counsels. The authors have used the document research method to clarify the formation and development of regulations on cases where the appointment of defense counsels for the accused persons is mandatory in Vietnam from the inception of the Democratic Republic of Vietnam on September 2, 1945 (the Socialist Republic of Vietnam now) until today, thereby showing the humanity of Vietnamese law in striving to increase further guarantee of the accused persons’ the right to defense. Moreover, the authors analyze and evaluate the existing limitations in the provisions on the cases of defense counsel appointment of the current Vietnamese law, as well as proposing solutions to perfect.