Biocomposites of waste expanded polystyrene (EPS) with sugarcane bagasse (SCB) powder were prepared through casting technique to produce plastic films. EPS was plasticized by using dioctyl phthalate (DOP) to overcome the rigidity of the recycled polystyrene and obtain flexible films. The loadings of bagasse powder were (5, 10, 15 and 20) wt. % with respect to polystyrene. The mechanical properties were maintained although some variations arose after loading polystyrene with bagasse. The hardness of these composites increased over that of plasticized polystyrene. The thermal stability of the prepared composites did not deteriorate upon loading EPS with SCB powder. The investigated EPS/SCB films displayed the capability to absorb moisture and to be used in packaging applications.