The rhodium particles can be electrodeposited on a glassy carbon electrode, previously modified with multi-walled carbon nanotubes (MWCNTs), by voltage cycling between 0.4V and-0.3 V vs. SCE (30 cycles) in 50 mM H2SO4 containing 4.0 mM RhCl3. This proposed modified electrode is useful to facilitate the electrocatalytic reduction of nitrate and nitrite ions in acid medium. The mechanism of the electrocatalytic reduction of nitrate and nitrite ions in the hydrogen region of potentials was critically considered using voltammetric and DC/pulsed amperometric detection techniques. The GC/MWCNT-Rh electrode shows interesting sensitivity and temporal reproducibility towards nitrite and nitrate reduction under constant and pulsed applied potentials, respectively. (C) 2014 Published by Elsevier Ltd.