The chemistry and volume fraction of gamma prime phase in IN-100, UD-520, and UD-710 superalloys after high-temperature exposure in service have been examined. In the three alloys after exposure the gamma composition remains nearly constant and the concentration of (Al plus Ti) in gamma prime phase increases, approaching the theoretical value of 25%. The results suggest that Cr, Mo, and W aim to occupy different sites in the gamma prime lattice in the three examined alloys.