Abstract: A method is described for the analysis of cytosine methylation patterns in genomic DNA samples. In the first method step, the genomic DNA is isolated from cells or other accompanying materials and bound essentially irreversibly to a surface. Then the DNA bound to the surface is treated, preferably with a bisulfite, in such a way that cytosine is converted into a base that is different in its base pairing behavior in the DNA duplex, while 5-methylcytosine remains unchanged. Then the reagents that were used are removed in a washing step. Finally, selected segments of the immobilized DNA are amplified in a polymerase reaction and the amplified products are investigated with respect to their sequence.