A virus concentration method was developed utilizing the electrostatic interaction among viruses, multivalent cations and membranes. A negatively charged membrane was used to adsorb viruses from water samples through which diluted sulfuric acid (pH3.0-4.8) was then passed to remove cations from the membrane, followed by the elution of viruses with alkaline solution (pH10.5-12) or with beef extract solution (pH9.5). F-specific RNA phage Qβ and poliovirus type I were used as model viruses and pure water, tap water and artificial seawater were used as samples. The method using a negatively charged membrane with acid rinse followed by alkaline elution showed the highest recovery yields among those tested for polioviruses including the 1MDS positively charged membrane, especially when applied to seawater. This method also has a potential advantage over conventional methods of using inorganic eluant such that there will be no inhibition of the subsequent virus detection by PCR.