The kit provides a fast and simple method to isolate genomic DNA from various blood samples including fresh whole blood, frozen blood, blood dried spots, serum, and plasma. It uses silica-membrane technology to eliminate the cumbersome steps associated with loose resins or slurries. It is ready for use and can purify the genomic DNA from a wide of blood source samples. The process is completed in less than 20 minutes: purified DNA suits PCR, restriction endonuclease digestion, and Southern Hybridization.