In this paper we describe the fabrication and characteristics of highly efficient and stable CdTe/CdS thin film solar cells. Our cells are prepared in three subsequent phases. Firstly, we deposit via sputtering, without solution of continuity a layer of CdS on top of the front contact made up of a double layer of ITO/SnO2 deposited on a soda lime glass substrate. The second phase consists in the treatment of the CdS layer, which is the key factor for the fabrication of a good heterojunction, with CdCl2 and in the subsequent deposition of the CdTe layer via close space sublimation technique. Finally, the back contact is fabricated via sputtering making use of the Sb,Te, compound which guarantees the cell stability. Under global AM1.5 conditions the open-circuit voltage, short-circuit current and fill factor of our best cell, fabricated without antireflecting coating and normalized to the area of 1 cm(2), were V-oc = 858 mV, J(sc) = 23 mA/cm(2) and ff = 74%, respectively, corresponding to a total area conversion efficiency of eta = 14.6%.