The Genomic DNA Isolation Reagent is a non-organic and ready-to-use reagent for the isolation of genomic DNA from human, animal （incl. mouse tail）, plant, yeast, bacterial and viral origin. It is an improved version of the Chomczynski method （1）, which is based on disruption of cells in a guanidinium-detergent lysing solution that hydrolyzes RNA and allows the selective precipitation of DNA from a cell lysate with ethanol. Following an ethanol wash, DNA is solubilzed in water or 8 mM NaOH. There is no phenol in the Genomic DNA Isolation Reagent. The protocol is fast and permits isolation of genomic DNA from a large number of samples of small or large volumes. The procedure can be completed in 10 - 30 minutes with DNA recovery of 70 - 100 %. The isolated DNA can be used, without additional purification, for Southern-analysis, dot blot hybridization, molecular cloning, RFLP, PCR and other molecular biology and biotechnology applications. A detailed application protocol is included.