Chalcopyrite-type CuInSe2 was successfully prepared by using mechanical alloying (MA) method. Various process parameters such as reaction system, rotational speed and milling period were investigated in detail. The determined best condition for the preparation of CuInSe2 was that the reaction system was Cu + In + 2Se --> CuInSe2, the rotational speed was 250 rpm and the milling period was 60 min. In the X-ray diffraction pattern of the CuInSe2 sample prepared by the MA, characteristic peaks of the chalcopyrite-type structure such as 101, 211 and 311 were clearly observed. The determined lattice parameters were a= 5.77590) Angstrom and c = 11.5950(l) Angstrom (c/a = 2.007). The crystallographic structure of the CuInSe2 sample was analyzed by Rietveld analysis using X-ray powder diffraction data. (C) 2003 Elsevier Science B.V. All rights reserved.