Independently identified over twenty years ago as a membrane glycoprotein of both platelets (Okumura and Jamieson, 1976; Podolsak, 1977) and milk fat globules (Kobylka and Carraway, 1973) that is highly resistant to proteolytic digestion, the primary function of CD36 remains something of an enigma. As will be discussed below, CD36 has been reported to bind a wide range of ligands, and reports that it is the thrombospondin membrane receptor (Asch et al., 1987) or a primary receptor for platelet collagen adhesion (Tandon et al., 1989a) have led to great controversy, with protagonists on both sides. The identification of a substantial proportion of Japanese blood donors that totally lack CD36 expression on platelets yet have no apparent haemostatic abnormalities (Yamamoto et al., 1990) served to heighten this controversy in the literature (Tandon et al., 1991; Kehrel et a1., 1991, 1993; Diaz-Ricart et al., 1993; Daniel et al., 1994). Notwithstanding subtle abnormalities that have been identified in in vitro studies of platelets from this population, the apparent healthy status of this phenotypic group probably suggests that any physiological role for CD36 as a receptor involved in platelet aggregation is minor. However recent evidence does indicate such individuals may be predisposed to development of the hereditary form of hypertrophic cardiomyopathy (Tanaka et al., 1997). Additionally, there is accumulating evidence that CD36 is functionally involved in the development of atherosclerosis (Endemann et al., 1993) and also in the clearance of apoptotic cells (Savill et al., 1992), as well as functioning as a receptor for erythrocytes infected with the malaria parasite Plasmodium falciparium (Oquendo et al., 1989). Therefore, further study of this intrinsically fascinating molecule is likely to prove rewarding and may lead to improvements in human health care.