Copper films were obtained by metal-organic chemical vapour deposition using hydrated copper formate. The films were deposited on Si(100) and sputtered TiN/Si(100) 4-in wafers, at substrate temperatures of about 300 degrees C, with a reducing or inert carrier gas. Results from X-ray diffraction and X-ray photoelectron spectroscopy indicated a pure, crystalline and oxygen-free copper. Different film morphologies were observed by scanning electron microscopy : both continuous films and inhomogeneous films with copper crystallites monodirectionally oriented were observed. In situ mass-spectroscopy analysis allows the proposal of some reaction mechanisms and highlights the importance of the initial hydration level of the precursor on the nucleation rate.