This review focuses on the structure, function and pathological role of leukocyte function-associated antigen-1 (LFA-1) which is a heterodimeric protein consisting of two subunits. LFA-1 plays a most important role in the immune system including adhesion, extravasation, migration, apoptosis, cytotoxicity, cytokine production, and proliferation of lymphocytes. Therefore, T-cell activation can be suppressed by blocking ICAM-1/LFA-1 interaction in autoimmune diseases and organ transplantation. Many different inhibitors (i.e. antibodies, peptides, small molecules) have been demonstrated to block ICAM-1/LFA-1 interaction, and some of them are promising for medical treatment or have reached clinical trials.