Ag nanoparticles were exclusively deposited inside the pores of the porous anodic alumina (PAA) template through the deposition cycle including the incubation and the subsequent reduction of Ag(NH3). Both the density and size of the produced Ag nanoparticles increased as the deposition cycle number increased. A field-emission scanning electron microscopeand an ultraviolet-visible spectrometer were applied, respectively, to study the morphology and the extinction spectra of the Ag nanoparticles. The optimum deposition number was found from the scanning electron microscope (SEM) analysis. Surface enhanced Raman scattering (SERS) spectra of p-aminothiophenol recorded on the Ag–PAA substrates prepared under increasing number of deposition cycles, manifested an enlarging trend of peak intensity. A point-by-point SERS mapping of p-aminothiophenol on the Ag–PAA substrate was acquired to characterise the homogeneity of the substrate. Copyright © 2008 John Wiley & Sons, Ltd.