Paracoccidioides brasiliensis is a dimorphic fungus, growing in its yeast form at 37˚C, and in mycelium form at 23˚C. Infection by P. brasiliensis is prevalent among rural farm workers in South America, Central America and Mexico, commonly affecting the lungs, lymphoid and mucocutaneous tissue. Attachment of fungal to animal cells and tissues is mediated by complementary molecules exposed on both fungi and host cellular surfaces. In this context, interactions between P. brasiliensis and components of the extracellular matrix (ECM) are thought to be the first step for establishment of paracoccidioidomycosis. The aim of this study was to further investigated the interaction of P. brasiliensis with ECM of human lung fibroblasts (CPF). P. brasiliensis (strain 18) was cultivated in liquid peptone/glucose/yeast extract medium at 36º C in a shaker at 100 rpm. Assays of adhesion of P. brasiliensis were carried out on: i) culture of human lung fibroblasts, ii) ECM components of confluent fibroblast cultures, which were treated with non-ionic detergent Triton X-100 0.1% in PBS at 4º C, condition in which most  fibroblast cytoplasmatic and membrane components are solubilized remaining in the culture plate an insoluble residue consisting of a fibrillar meshwork matrix,  and iii) on polystyrene plates were coated with fibronectin or laminin. The fungi were incubated for 1 hour in DMEM medium containing 1% of FCS at 37˚C. After this period, the non-adherent fungi were removed by washing the plates exhaustively with DMEM medium, and P. brasiliensis attached to the plates were fixed with formaldehyde 4% and stained with Lactophenol Cotton-blue, or Grocott-Gomori methenamine silver or Calcofluor white. A dose-dependent adhesion of yeast to immobilized laminin and fibronectin was observed, low coating concentration of laminin (0.2µg) resulted in high adherence of fungal cells. For fibronectin higher concentration (2.5µg) was necessary for fungal adhesion. It was also observed a significant adhesion of P. brasiliensis to lung fibroblast cultures, and to detergent-insoluble fibroblast matrix. SDS-PAGE analysis of detergent-insoluble fibroblast matrix, at reducing condition, showed presence of (glyco)proteins of 220kDa (corresponding to fibronectin), 130kDa; 110kDa; 58kDa, 40kDa and 24kDa. The role of these fibroblast (glyco)proteins as adhesion molecules for P. brasiliensis is under investigation.