The present invention is directed to antibodies and binding fragments thereof,which bind with high affinity andspecificity to human P-selectin glycoprotein ligand 1 (PSGL-1) and which blockboth selectin and chemokine binding to PSGL-1expressed on leukocytes, lymphocytes and endothelial cells and thus whichinhibit migration and/or rolling of these cells and tomethods for screening for such antibodies and binding fragments thereof and tomethods of therapeutic use thereof.