The preparation and characterization of NiTe2 back contacts to CdTe/CdS cells are described. NiTe2 is formed on p-CdTe by electroless deposition at low reductant concentrations, producing devices that are superior (conversion efficiencies often exceeding 10%) to those contacted with electroless Ni. X-ray photoelectron spectroscopy and X-ray diffraction showed the product to be nickel(II) ditelluride (Ni2+Te2-2), produced, in the catalytic presence of Al3+ ions, by the reaction of Ni2+ ions with a Te-rich CdTe surface, which is formed by an in situ etch in the chemical bath. Preliminary results indicate that Ni, from NiTe2, is not mobile within the cell structure, which is expected to be favorable for stability. Cells exhibit degradation when exposed to H2O vapor. However, this effect was found to be reversible, with performance improving to near predegradation values following cell transfer to dry air conditions.