Direct measurement of the surface recombination velocity (SRV) on etched CdS(1120) and at its interface with Cu (deposited by aqueous CuSO4 solutions and in situ thermal evaporation) was achieved by using ultrafast time-resolved photoluminescence. Correlation with interfacial composition and chemistry was based on Auger electron spectroscopy (AES) and atomic absorption spectroscopy. The surface electronic structure was studied by using surface photovoltage spectroscopy. The results show that the original CdS SRV increases sharply as a function of Cu coverage. The SRV stabilizes around 1 × 106 cm/s (3 orders of magnitude above the clean surface value) at Cu coverage of about 1 monolayer, as estimated from AES results on in situ deposited Cu/CdS. The results are explained in terms of Cu-S compound-derived recombination centers at the Cu/CdS interface. The results are compared with thermally evaporated Cu/CdS interfaces, where a similar Cu coverage dependence and SRV mechanism are apparent.