Abstract: A process and apparatus for purifying DNA which has relatively high molecular weight from a biological sample containing DNA is described. The method comprises the steps (1) lysing the red blood cells in the sample; 2) lysing DNA-containing cells; (3) precipitating the proteins from sample; and (4) and rehydrating and recovering the DNA. method offers the advantages of performance in less than 15 minutes, not requiring organic or poisonous materials, compatibility with most anticoagulants, and requiring less solutions than conventional purification procedures, thus making it simpler and more economical to use.