During mammalian spermiogenesis a spherical spermatid is transformed into a highly asymmetric sperm cell. Concurrently, the plasma membrane of the cell develops into a mosaic of discrete membrane regions, with each region containing a unique set of proteins. Biogenesis of these surface domains was studied by following the surface expression and localization of nine different antigens during spermiogenesis. Each of these antigens exhibits one of four distinct patterns of localization on testicular sperm (whole cell, whole head, anterior tail, and posterior tail), indicating that there are at least three distinct surface domains on testicular sperm. Our results on the timing of antigen localization suggest that the generation of surface domains in mammalian sperm is a complex process. This process involves temporal and spatial regulation of surface expression of the antigens, as well as the specific removal of antigens from inappropriate domains after they have reached the cell surface.