In this paper, we consider a Joint Channel Network Coding (JCNC) scheme applied to Multiple Access Relay Channel (MARC) for correlated sources. Then, two correlated sources send their messages to one destination and one relay which performs network coding and provides additional information to the receiver. At the destination, a joint iterative decoding algorithm is developed which takes into account the correlation between sources. The proposed system is compared to Separate Channel Network Coding (SCNC) where the decoding process at the destination is done separately. Simulation results show that by using the JCNC process and exploiting the correlation between sources, the BER is significantly decreased at the destination.