Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)/expanded graphite films were cast as thin films with different expanded graphite contents at room temperature. The thermoelectric properties of the composites were investigated as a function of the graphite concentration. The electrical conductivity and Seebeck coefficient were measured as a function of the graphite concentration. The electrical conductivity and power factor show similar trends with a sharp increase at around 55 wt% of expanded graphite content. The Seebeck coefficient does not show a significant dependence with the graphite content. SEM and TEM images indicate a nearly homogenous distribution of the filler in the matrix. The initial thermal stability is not modified with the filler.