Method for isolating DNA contained in a biological sample. The method includes combining in a solution a DNA-containing biological sample, a salt, a cationic surfactant, and a DNA-binding carrier, the solution having a salt concentration higher than the DNA precipitation inhibition-initiating concentration, to lyse the DNA-containing biological sample and to bind DNA to the DNA-binding carrier while in the solution to form a bound DNA-carrier. The method also includes separating the DNA-bound carrier from other components. The method further includes dissociating the bound DNA from the DNA-binding carrier. The method still further includes recovering dissociated DNA.