Possibilities of using the γ rays excited by bombardment of an element with heavy charged particles to determine its isotopic abundances are discussed. With necessary facilities, this method, essentially a microanalytical or ultramicroanalytical method, would be convenient, especially if. a sample containing definite isotopic abundances is used as a standard for comparison. Nuclear reactions and γ rays suitable for the determination of isotopic abundances of Li, B, C and N are enumerated.