In this work, floating photocatalysts based on composites of low density polyethylene (LDPE) containing 30, 68 and 82 wt.% of TiO2 P25 were prepared and characterized by Scanning Electron Microscopy, Powder XRD data, surface area (B.E.T. method) and Thermogravimetric analyses. Degradation of the model dye methylene blue with UV (Hg 245 nm) and solar irradiation under constrained conditions, i.e. non-stirring and no-oxygenation showed excellent results. Under the same conditions pure TiO2 showed very low activities. The floating photocatalyst can be reused for at least three consecutive times without any significant decrease on the discoloration and Total Organic Carbon removal after each reuse.