Genomic DNA contamination is effectively removed using DNase treatment. The purified total RNA is ready to use and is ideally suitable for downstream applications that are sensitive to low amounts of DNA contamination, such as quantitative, real-time RT-PCR. The purification RNA can also be used in other applications including: RT-PCR, Northern blotting, nuclease protection assays, cDNA library preparation after poly (A)+ selection, and so on. Samples are first lysed and homogenized in a highly denaturing guanidine-isothiocyanate-containing buffer, which immediately inactivates RNases to ensure isolation of intact RNA. After homogenization, ethanol is added to the lysate to provide appropriate binding conditions for RNA, and the sample is then applied to an RNA spin column, where total RNA binds to the membrane. Genomic DNA is removed by DNase treatment and Contaminants are effectively removed by subsequent washing. The purified total RNA is then eluted with Elution Buffer.