The present study is focused on low-cost preparation of thin film TiO2/CuInS2 nanocomposite three-dimensional (3D) solar cells. With the aid of a simple spray deposition method, we have been able to obtain 3D solar cells, with a remarkable energy conversion efficiency of 5%. The new 3D solar cell design has the potential to breakdown the price barrier and to open up new production technologies for low-cost photovoltaic solar cells.