A multi-walled carbon nanotube (MWCNT) modified with zinc/aluminium layered double hydroxide-3(4-hydroxyphenyl) propionate nanocomposite (Zn/Al-LDH-HPP) was employed to prepare a chemically modified carbon nanotube paste electrode (CMCNTPE) for Hg(II) determination by cyclic voltammetry. The results indicated that Zn/Al-LDH-HPP nanocomposite has enhanced the sensitivity of the voltammetric responses. Under optimum experimental conditions such as percentage of modifier, pH of solution, type of supporting electrolyte, scan rate and regeneration, a linear relationship between concentration and current was observed within the concentration ranges of 1.0 × 10-9 - 1.0 × 10-7 M and 1.0 × 10-7 - 1.0 × 10-3 M Hg(II). The detection limit was found to be 5.0 × 10-10 M. Interferences of several metal ions were studied and showed that they did not interfere in the determination of Hg(II). The proposed CMCNTPE was one of high sensitivity, selectivity, repeatability and reproducibility. It has been used for the determination of Hg(II) in real samples such as fish and shellfish with success.