Thin CoO oxide layers with superior properties in terms of crystallographic ordering, surface roughness and constant and controlled chemical compositions have been prepared by pulsed laser deposition in reactive O2 atmosphere at 400°C. Such systems are particularly suitable both for applications and for basic studies, any time high quality and controlled surfaces are required, for example in multilayered systems whose behaviour critically depends on interface properties, such as magnetically exchange-coupled systems. A structural and microstructural study of such films is presented, together with the compositional analysis for different process conditions. The best control on film stoichiometry was obtained by protecting the surface with a thin Pt cap-layer, before air exposure.