The present invention relates to a method for extracting circulating nucleic acids from a biological fluid. The method comprising the successive steps of providing the biological fluid supposed to contain the circulating nucleic acids. Then the biological fluid is contacted with a lysis solution comprising at least a chaotropic agent, a binding solution comprising at least a PEG derivative designed for cooperating with at least part of the circulating nucleic acids, wherein the binding solution is free of ethanol and isopropanol, and a solid support capable of capturing at least part of the circulating nucleic acid. Finally, the solid support is separated from the lysis solution, from the binding solution and from the biological fluid.