AbstractWe have localized the mRNA of the epidermal growth factor receptor (EGF‐receptor) in nuclei of A431 cells by non‐radioactive in situ hybridization at the light microscopical level using digoxigenin‐labelled DNA probes. Both formaldehyde and glutaraldehyde fixations were tested before the hybridization was performed. Glutaraldehyde, compared with formaldehyde fixation, gives a less diffuse hybridization signal, which is easier to localize. Therefore, glutaraldehyde was used as a fixative in the hybridization experiments. It is demonstrated that the mRNA of the EGF‐receptor is present in restricted domains mainly located around the nucleolus. This location of the EGF‐receptor mRNA was unaltered after extraction of chromatin. Therefore it is concluded that the messenger RNA of the EGF‐receptor is attached to the nuclear matrix. A possible biological role for the location of mRNA of the EGF‐receptor around the nucleolus