ABSTRACT:The expansion formula has been presented for Slater-type orbitals with noninteger principal quantum numbers (noninteger n-STOs), which involves conventional STOs (integer n-STOs) with the same center. By the use of this expansion formula, arbitrary multielectron multicenter molecular integrals over noninteger n-STOs are expressed in terms of counterpart integrals over integer n-STOs with a combined infinite series formula. The convergence of the method is tested for two-center overlap, nuclear attraction, and two-electron one-center integrals, due to the scarcity of the literature, and fair uniform convergence and great numerical stability under wide changes in molecular parameters is achieved.