This paper presents a MAC-PHY cross-layer analysis of a narrow-band power line communication (NB-PLC) system in the presence of impulsive noise. We consider a CSMA/CA based MAC layer along with the impulsive noise in PHY layer modeled as a Bernoulli-Gaussian process. We calculate the bit error rate (BER) for such an NB-PLC system with two-level amplitude-shift keying (ASK), binary phase-shift keying (BPSK), and binary frequency-shift keying (BFSK) as the signaling schemes. This BER is then incorporated in MAC layer to analyse throughout, reliability, and average wait time performances. From numerical results, it shown that for a fixed signal-to-noise ratio (SNR), the MAC layer performance degrades with increasing average occurrence of impulsive noise. Further, for a fixed SNR, the superiority of the BPSK is shown over ASK and BFSK. It is also shown that for a fixed SNR the throughput decreases with increasing number of devices. Hence, we motivate a redesign of the MAC layer protocol for NB-PLC network to handle a large number of devices. © 2018 IEEE.