Co1-xFexSb3 skutterudites were synthesized by encapsulated induction melting and their thermoelectric properties were investigated. Single phase δ-CoSb3 was successfully obtained by the subsequent heat treatment at 773K for 24 hours in vacuum. However, δ-CoSb3 was decomposed to FeSb2 and Sb when x≥0.3, which means that the solubility limit of Fe to Co is x<0.3. The positive signs of Seebeck coefficients for all Fe-doped specimens revealed that Fe atoms acted as p-type dopants by substituting Co atoms. Thermoelectric properties were remarkably enhanced by Fe doping and optimum composition was found to be Co0.7Fe0.3Sb3 in this study.