Abstract: Over recent years CuInS2 (CIS) has emerged as a promising absorber material for solar cells. The historical development and current status of cells based on CIS thin film are reviewed. The microstructure and material properties, preparation techniques, reaction kinetics, the influence of incorporating additional elements and post-growth treatments, and the buffer layers of CIS are described. A brief description of industrial CIS solar cells and the low-cost technology employing electro-deposition and sulfurization to prepare the thin film is also given. The future of these solar cells is assessed.