In this research gold nanoparticles (AuNPs) were synthesized by using aqueous extract of Elaeis guineensis (oil palm) leaves. Effects of reaction time on rate of reduction, size of particles and stability of gold nanoparticles were investigated. Reduction of gold precursor to form gold nanoparticles was monitored by recording SPR wavelength on a UV-vis spectrophotometer. SPR wavelength and maximum absorbance of the reaction medium reached a plateau after 60 min of reaction indicating complete reduction of gold precursor to gold nanoparticles. DLS measurements showed that polydispersed gold nanoparticles with average hydrodynamic diameter of 55.22 ± 42.86 nm were formed during the AuNPs synthesis reaction. Synthesized gold nanoparticles with zeta potential value of -14.7 mV were stable for 30 days. © 2016 The Authors. Published by Elsevier Ltd.