The present invention relates to a method for separating viruses from a contaminant-containing liquid medium using two adsorbents having cationic groups, wherein the viruses are adsorbed to the first adsorbent and subsequently eluted and wherein the contaminants present in the resulting eluate are subsequently adsorbed to the second adsorbent. The yield and purity of the viruses obtained as per the method according to the invention is increased by the addition of multivalent anions during the adsorption of the contaminants to the second adsorbent.