Electronic Raman scattering (ERS) has been used to study residual shallow acceptors in undoped semi‐insulating (SI) GaAs grown by the liquid‐encapsulated Czochralski technique. The dispersion of the cross section for ERS of shallow acceptors, as well as its absolute value, has been measured. It is shown that ERS allows a quantitative analysis of residual shallow acceptors in SI GaAs. Calibration factors for C and Zn acceptors are given. The detection limit of ERS is determined to ∼5×1014cm−3for 500‐&mgr;m‐thick standard wafers. Spatially resolved measurements show a systematic variation of the residual acceptor concentration across 2‐in. GaAs wafers.