An attempt was made for preparing CIGS absorber layers by one-step sputtering of a quaternary target for eventual use such as large area CIGS solar cells. For fabricating the layers, a single quaternary target with pre-determined compositions of the constituents, Cu, In, Ga and Se was employed and the in-situ and post-annealing by RTP were performed. Then the layers were characterized by SEM, AFM, XPS, XRD and EDX. Indeed, the CIGS absorber layers with chalcopyrite structure could be successfully obtained. In addition, it was found that the very smooth surfaces could be obtained since the deposition was conducted by single-step sputtering. The present work shows that the one-step sputtering method can be a potential route for the economic preparation of CIGS absorber layers.