An alternative route for the production of graphene-polymer nanocomposites is proposed. First graphene oxide lamellae are homogenously dispersed in a polyvinyl alcohol matrix. In a second step, mild thermal treatments are carried out on composites in order to promote a thermal reduction of the graphene oxide into reduced graphene oxide. The occurrence of an in situ reduction of graphene oxide is confirmed by various experimental techniques, such as differential scanning calorimetry, thermogravimetric analysis and electrical resistivity measurements.