The aim of this study was to synthesise and characterise nanogold-{[(Cu)(phen)(cys)(H2O)]NO3}n conjugate and to evaluate its antiproliferative property against breast cancer cell line (MCF7) and normal cell line (MCF10A). Nanogold solution was prepared using Turkevish method. In one approach, ternary copper(II) complex of 1,10-phenanthroline with amino acid L-cysteine, [(Cu)(phen)(cys)(H2O)]NO3, was first prepared and then tethered with the gold nanoparticles. In another approach, gold nanoparticles were reacted with L-cysteine, copper(II) nitrate, and 1,10-phenanthroline subsequently. The synthesized [(Cu)(phen)(cys)(H2O)]NO3 complex was characterised using fourier transform infrared (FTIR) and electrospray ionisation mass spectrometry (ESI-MS) techniques. FTIR and ESI-MS results show that L-cysteine was bound to the copper through carboxylic and amino groups, with the thiol moiety of L-cysteine remained free. The free thiol group bound to the nanogold surface to complete the nanogold-{[(Cu)(phen)(cys)(H2O)]NO3}n conjugate formation. Nanogold-{[(Cu)(phen)(cys)(H2O)]NO3}n conjugates were characterised using FTIR and UV-Vis spectroscopy. The increase in the surface plasmon absorption band in UV-Vis and absence of thiol peak in FTIR of the conjugate showed that the thiol group of L-cysteine was bound to the gold nanoparticle to form the conjugate. Moreover, the formation of the conjugate is also evidenced from the colour change from ruby red to blue. Anticancer property of the nanogold bound conjugate and unbound analogues was examined using MTS assay on breast cancer cell line (MCF7) and normal cell line (MCF10A). It was concluded that [Cu(phen)(cys)(H2O)]NO3 copper(II) complex was successfully prepared and tethered with nanogold particles. The prepared nanogold-{[(Cu)(phen)(cys)(H2O)]NO3}n conjugate was tested for its antiproliferative activity which showed better antiproliferative property towards the breast cancer cells than the unbound analogues.