Sperm develop in the seminiferous tubules of testis following a complex developmental process called spermatogenesis. A series of morphological remodeling occurs during spermiogenesis before the sperm are released into the lumen of the tubules by spermiation (Eddy and O'Brien, 1994). Mammalian testicular spermatozoa are relatively non-motile and incapable of fertilizing the ovum. In most of the species, sperm attain progressive motility and fertilizing capacity during their transit through various regions of epididymis. Several changes in the sperm membrane and in the cytoplasm, by addition and deletion of several proteins and molecules, occur during the epididymal transit (Moore, 1990). During ejaculation, sperm are exposed to various components of the seminal plasma that adhere on the sperm membrane. The ejaculated sperm are incapable of fertilizing the oocyte. They must undergo several physiological changes that are collectively called capacitation leading to acrosomal exocytosis during the transit through the female genital tract (Yanagimachi, 1994). One of the major steps besides tyrosine phosphorylation during capacitation is the removal of seminal plasma adsorbed proteins from the sperm surface (Naz and Rajesh, 2005). These changes are prerequisite for successful fertilization. It is generally believed that these processes are regulated by several hormones and cytokines/growth factors present in seminal plasma and female genital tract. The receptors for several hormones and cytokines/growth factors have been reported present on the sperm membrane and the list is ever-growing. The sperm are transcriptionally and translationally quiescent, and they can be successfully capacitated in vitro without any hormone and cytokine/growth factor. In lieu of these findings, the physiological significance of several of these receptors seem enigmatic, probably doubtful. The present article will review the receptors for well known hormones/growth factors/neurotransmitters that have been reported in the literature, and discuss their authenticity and physiological relevance. The cognate proteins on the sperm surface that have been delineated by using monoclonal and polyclonal antibodies (at least >100) and have been implicated in various sperm functions, especially oocyte zona pellucida binding, have been excluded from this review (Anderson et al, 1987; Eddy and O'Brien, 1994; Naz et al, 2005). Only receptors that are well known and have a definite role in other cell types are included.