On dried filter paper coated with silver nanoparticles, surface-enhanced Raman scattering (SERS) spectra of p-hydroxybenzoic acid (PHBA) were studied, and high-quality SERS spectra were obtained, indicating that the silver-coated filter paper is a highly SERS-active substrate. The analysis showed that the adsorption behavior of PHBA molecules on silver nanoparticles coated on filter paper was different from that in silver aqueous colloids. On the filter paper, it was found that the SERS spectra of PHBA changed with the proportion of PHBA molecules and silver nanoparticles, indicating that the adsorption behavior of PHBA molecules changed with the proportion. The probable reasons are given. (C) 2003 Elsevier Inc. All rights reserved.