A morphological study of the vas deferens of the pigeon was carried out in order to determine the electronmicroscopic features of its epithelial lining, and the expression of pancytokeratins. The results showed that the epithelium is columnar pseudostratified and consists of non-ciliated (principal) cells and basal cells. Presence of a predominantly granular endoplasmic reticulum, mitochondria and well-developed Golgi complexes bearing vesicles on their cis/trans surfaces were observed. In addition to these vesicles associated with the Golgi complexes were observed membrane-delimited vesicles with a low electron density content or with an electrondense content mainly related to the endoplasmic reticulum. Apical cytoplasmic expansions with heterogeneous cytoplasmic content were also seen. These subcellular features associated to the presence of pancytokeratins, suggest the occurrence of a secretory process in principal cells, as well provide a mural structural support to the vas deferens.