Power line communication (PLC) is one of the preferred broadband high-speed data communication technology for its wide availability, low infrastructure cost, and robustness. However, PLC performance is limited by attenuation and background noise present in the medium. The frequency shift keying (FSK) modulation scheme is experimentally found to be more robust against such power line distortions. Further, it was shown earlier that the background noise in PLC follows Nakagami-m distribution. In this paper, we have evaluated bit error rate (BER) of coherent and non-coherent binary FSK, when corrupted with background Nakagami noise. The derived expressions are simple, involve only elementary functions, and the analytical BER values match perfectly with computer simulations. It is found that the noise parameter m has a marked influence on the BER performance.