The underpotential deposition of lead was studied on spherical and faceted gold nanoparticles. On 21.7 nm spherical nanoparticles, a single stripping peak from Au(111) face was observed at -0.2 V, whereas on 82 nm faceted gold nanoparticles the peak split in to two at -0.2 V and -0.18 V vs Ag/AgCl (3 M KCl). The roughening of the Au(111) terraces by electrochemical treatment leads to the suppression of the spike. It appears that the extent of surface crystallinity of nanoparticles causes the observed differences in the upd-stripping behaviour. The splitting of the Pb-upd stripping peak from Au(111) face can be used as an indication for the surface crystallinity of gold nanoparticles.