Raman scattering of vibrational modes of Cl in CdS is reported. From the resonance enhancement of these modes with excitons bound to Cl atoms they are identified with either (1) isolated Cl atoms or (2) complexes consisting of a Cl atom and an adjacent Cd vacancy. Our results support an earlier suggestion of Thomas et al. that Cl-Cd vacancy complexes form shallow acceptors in CdS. © 1978.