The design of affinity adsorbents based on lectin/carbohydrate interactions constitutes an alternative tool in mammalian glycoprotein production processes. It is reported that many fungal lectins targets their specificities towards oligosaccharides which are present in these glycoproteins, thus constituting highly potential ligands in the development of affinity adsorbents. The Microbiology Department at the Faculty of Chemistry possesses an important collection of basidiomycete fungi collected in Uruguay and also, from edible mushrooms producing companies. The present work reports a screening for lectins in aqueous extracts prepared from 21 species of basidiomycete fungi using mycelia and/or fruiting bodies. The lectin presence was determined by hemagglutination (HAG) assays using red cells of different sources and by inhibiting this HAG by specific carbohydrates. A total of 42 carbohydrates, including mono-, di- and trisaccharides, glycoproteins and polysaccharides, were tested. Extracts prepared from Dietyoparus pusollus, Ganoderma resinaceum, Abortiporus biennis and Gymnopolus speerabilis, only caused positive HAG against rat red cells, being this HAG clearly inhibited by the glycoproteins Fetuin and Chorionic Gonadotrophin and, in some cases, the Thyroglobulin. When using rat red cells, 13 extracts were positive for HAG. Based on the interesting levels of HAG of extracts prepared from Pleurotus ostreatus, the purification of this lectin was assayed, in order to produce the lectin in adequate amounts for its further immobilization on Sepharose support. As the lectin is specific for galactose and its derivatives, an affinity chromatography on synthesized Galactosyl-Sepharose, was performed. The eluted lectin was immobilized on NHS-activated Sepharose and this adsorbent contains 0.5 mg of immobilized lectin per ml of packed gel. The performance of this affinity adsorbent towards the glycoproteins adsorption, is under progress. We thank the financial support from CSIC-Productivo (No. 325) and PEDECIBA-QUIMICA.