The concentrations of donors (ND) and acceptors (NA) in a high‐quality GaAs epitaxial layer sample are determined by the optical method. The numerical values ofNDandNAare deduced from the limiting values of combinations of the excitation‐dependent integrated emission intensities due to the conduction‐band–to–neutral‐acceptor, neutral‐donor–to–valence‐band, and neutral‐donor–to–neutral‐acceptor transitions.