New amorphous molybdenum oxysulfides have been obtained by r.f. sputtering and have been characterized. Their chemical composition depends on the partial pressure of oxygen introduced into the sputtering chamber during preparation. IR and extended X-ray absorption fine structure studies have confirmed previous results obtained by X-ray photoelectron spectroscopy. Depending on the composition, three kinds of molybdenum have been identified with different surroundings : one with only oxygen, one with only sulfur, and the last with oxygen and sulfur. The electrical conductivity also depends on the composition : best values have been obtained with a low oxygen content. Finally, the densities of these molybdenum oxysulfides are much lower than those of crystalline molybdenum oxides (MoO2, MoO3) or sulfide (MoS2). These materials are good candidates as positive electrode materials in microbatteries.