Most of the scientific works deal with epididymal sperm maturation but not sperm storage. Therefore, this book was based on the experiments carried out to determine sperm transfer times in different regions of hamster epididymis, sperm storage time in the cauda epididymis and functional ability of cauda sperm after placing ligations. To study the sperm transfer times and retention times in different regions of the hamster epididymis, initial segment was blocked by a ligation at the junction between the initial segment and the caput region. Ligation of epididymal tubule at the junction between the distal corpus and the proximal cauda was carried out to determine the storage time of the hamster cauda epididymal sperms. Fertilization ability of hamster sperm after cauda ligation, was investigated using in vitro fertilization technique and Ca2+ ionophore was used to induce capacitation and acrosome reaction of hamster sperm in different post-ligation days. Findings of this book should be helpful to researchers to find a proper explanation for sperm storage in cauda epididymis.