The oligosaccharide sequences of glycoconjugates in the normal human vas deferens and the nature of the saccharide linkage were studied by lectin histochemistry. The cytoplasm of all epithelial cell types (principal cells, basal cells, and mitochondria-rich cells) and luminal contents reacted positively with WGA, MAA, PNA, DSA, LTA, UEA-I, AAA, and ConA. The reaction was more intense in the stereocilia of principal cells. Cytoplasmic staining was diffuse except for PNA and DSA labeling which was limited to the apical cytoplasm and stereocilia of columnar cells. The cytoplasm of all cell types also reacted diffusely with HPA, although staining was weak and was not observed in the stereocilia. Positive reaction with SBA only was encountered in the stereocilia of principal cells. SNA, LTA, and DBA were unreactive. GNA-labeling showed a granular distribution in the supranuclear cytoplasm of columnar epithelial cells. Reactions with MAA, PNA, DSA, AAA, HPA and SBA disappeared after the β-elimination reaction. Reactions with WGA and UEA-I decreased after β-elimination or Endo-F digestion. Reactions with ConA and GNA were suppressed by Endo-F digestion. Reactions with PNA, HPA, and SBA increased after desialylation. Of all the lectins that label the luminal contents of the vas deferens, only UEA-I was not found in the luminal contents of seminiferous tubules and epididymis and, thus, this lectin would probably bind to glycoproteins secreted by the vas deferens. The chemical treatments used suggest that this secretion contains fucose residues located in both N- and O-linked oligosaccharides. The other lectins may label secreted proteins, but also structural proteins or proteins reabsorbed from the luminal fluid. The lectin- binding pattern of mitochondria-rich cells in the vas deferens differed from that found in the epididymis.