Incorporation of N and S containing porous graphite (NSPG) in the composition of carbon paste electrodes (CPEs) can improve their sensing behavior. Result of former studies have indicated the selective interaction of N, N-bis(a-methylsalicylidene) diethylenetriamine (BMT) and Pr3+ ions, as opposed to other lanthanide ions. In this light, BMT was incorporated into a mixed matrix of NSPG and graphite powder to obtain a modified Pr3+ potentiometric sensor. The results indicated that the nano-composite sensor offers enhanced sensitivity, selectivity; response time; response stability and lifetime in comparison to CPEs modified using multiwall carbon nanotube (MWCNT). The optimal response (i.e. a Nernstian response of 19.7±0.3 mV per decade from 1.0×10-7 to 1.0×10-2 mol L-1) was observed for a sensor containing 10% NSPG, 15% BMT, 30% IL and 45 % graphite powder.