The present invention provides a cell adhesion molecule (CAM), designated F11 receptor (F11R), which is a member of the immunoglobulin super family localized on the surface of human platelets, and determined to effect platelet aggregation, secretion, platelet spreading and cellular adhesion. Cloned F11R cDNA and full length F11R cDNA and amino acid sequences are provided. F11R-antagonists and methods for the prevention and treatment of thrombosis, atherosclerosis, heart attacks, stroke and other clinical disorders involving thrombus formation are also provided.