This review describes the present state of science and technology of photopolymerizable (UV-curable) polyurethane (PU) nanocomposites which include nanosilica and organically-modified clay (organoclay). A number of documented improvements of properties of PU nanocomposites compared to the pristine PU are presented. Many data on the structure and properties of PU nanocomposites were obtained not only for UV-cured urethane acrylate oligomers, but also for nanocomposites produced in the dark reactions. These data are critically reviewed. There is an expectation in the field of dramatic improvement of properties of PU nanocomposites under low loading (1-5 wt%) of organoclay.