Integrins, which are composed of an alpha and beta subunit, are capable of binding to a number of extracellular matrix proteins and, hence, affect cell adhesion and proliferation.The distribution of the integrin beta (beta 1, beta 3-beta 5) and alpha (alpha 1-6 and alpha v) subunits in human anterior chamber angle was studied in eyes from subjects aged 9 months to 81 years using the indirect immunofluorescence technique.Immunoreaction for the beta 1 subunit was found throughout the trabecular meshwork (TM), in the cribriform layer, and in the endothelial lining of Schlemm's canal (SC). Labelling for the alpha 3 subunit was found in the TM and the cribriform layer only. In infant eyes the alpha 5 subunit was present in all three areas with the highest concentration in the cribriform layer, whereas no reaction was observed in adult eyes. The alpha 6 subunit was localized to the endothelium of SC only. Immunoreaction for the alpha v subunit was present in the TM and the cribriform layer of infants and young adults.The present results suggest the presence of several integrin heterodimers, acting as potential receptors for laminin, collagen, fibronectin, and vitronectin, in the anterior chamber angle.