‎in this paper a new family of fifteenth-order methods with high efficiency index is presented‎. this family include four evaluations of the function and one evaluation of its first derivative per iteration.‎ ‎therefore‎, ‎this family of methods has the efficiency index which equals 1.71877‎. ‎in order to show the applicability and validity of the class‎, ‎some numerical examples are discussed‎.