A method for purification of a nucleic acid comprising the steps of (a) adsorbing on a substrate the nucleic acid from a composition containing (i) an aqueous buffer, (ii) salts in a high concentration, (iii) a water-miscible, non-acidic organic compound, and (iv) the nucleic acid; (b) optionally washing with a washing solution the substrate with the adsorbed nucleic acid; (c) contacting the substrate with the adsorbed nucleic acid with a solution containing salts in a lower concentration compared to the composition of step (a), thereby desorbing the nucleic acid from the substrate; (d) separating the solution with the desorbed nucleic acid from the substrate, thereby purifying the nucleic acid; and optionally (e) precipitating the desorbed nucleic acid from the solution of step (d) and isolating the precipitated nucleic acid, thereby further purifying the nucleic acid.