The paper presents the results of studying the processes of electric charge transfer in polymer nanocomposites based on polyphenylene oxide with fullerene C60 (1% and 8%) and with endometallofullerene Fe@C60 (1%) as nanofillers. The existing theoretical models were used to calculate the values of the charge transfer parameters, such as the carrier concentration N, the mean free path Rω, and the height of the potential barrier W. The conductivity type was determined for all samples by analyzing the temperature dependences of the exponent s.