This work evaluates the expression in lung cancer of the most well characterized mucin genes (MUC1, MUC2, MUC3) and of the recently described MUC4 in lung tissues, to check a correlation between the expression of any particular gene and this tumor. Hybridization with synthetic oligonucleotides obtained from a part of the sequences of MUC1, MUC2, MUC3 and MUC4, was performed on blotted RNA from 18 lung cancer tissue specimens and from 10 normal tissues samples taken, when possible, from the normal lung counterpart. By means of Northern blot analysis MUC1 revealed to be the most expressed mucin gene in lung cancer, followed by MUC4; by contrast, the expression of MUC2 and MUC3 was almost undetectable in all cancer specimens. The intensity of expression of MUC1 and MUC4 was always superior in cancer tissue than in the normal counterpart. As expected, the highest reactivity for MUC1 and MUC4 expression was observed mainly in the adenocarcinoma histotype which is mucin secreting. These findings represent a contribution to the study of mucin gene pattern in lung cancer, and, in particular, indicate that MUC4, in association with the MUC1 gene, seems to be strongly expressed in this neoplastic disease.