Thin films of zinc hydroxo-sulphide were prepared by chemical bath deposition (CBD) in alkaline ammonia solutions containing a zinc salt, thiourea as sulphur precursor and different amine additives. The alms were characterized by extended X-ray absorption fine structure (EXAFS) and infrared spectroscopy. A detailed simulation of ZnS, Zn(OH)(2) and ZnO EXAFS functions showed that the composition corresponded to zinc hydroxo-sulphide and that the ratio between the hydroxyl and sulphur concentrations depended on the bath composition.