Adipophilin (ADFP, adipocyte differentiation-related protein) is a peripheral membrane located in milk lipid globules. Adipophilin is involved in the development and maintenance of adipose tissue. Adipophilin, previously believed to be specific to adipocytes, is a major constituent of the globule surface and is present in a detergent-insoluble complex that contains stoichiometric amounts of butyrophilin and xanthine oxidase. Adipophilin is expressed in a wide range of cell lines, including fibroblasts, endothelial and epithelial cells. In tissues, it is restricted to certain cell types, such as lactating mammary epithelial cells, adrenal cortex cells, Sertoli and Leydig cells of the male reproductive system, and steatosis or fatty hepatocytes in alcoholic liver cirrhosis. Adipophilin is a possible new marker for the identification of specialized differentiated cells containing lipid droplets and for diseases associated with fat-accumulating cells.