Polycrystalline samples of (CuInSe2)1—x(VSe)x alloys have been prepared by the usual melt and anneal technique in the composition range 0 ≤ x ≤ 0.5. X-ray diffraction (XRD), differential thermal analysis (DTA) and scanning electron microscopy techniques were used to characterize the products. By SEM, the stoichiometry of the samples was checked finding that the difference between nominal and experimental stoichiometry is, in any case, less than the estimated experimental error (∼10%). XRD measurements showed a tetragonal chalcopyrite-like structure in the entire composition range studied, with traces of a secondary phase at x ≥ 0.2. The observed peaks for this secondary phase do not match with the known crystallographic data for VSe or VSe2 and stay unknown for the moment. The analysis of DTA data suggests an independent compound at x ∼ 1/3.