Declining in reproductive efficiency is a worldwide problem, although remarkable progress has been made in reproductive techniques including artificial insemination programs, estrous cycle synchronization, and effective embryo production. One means of solving this problem is to select breeding cows based on highly precise diagnosis for high reproductive ability, including ovarian and uterine function. Many recent studies have documented the regulation of uterine function, with the results suggesting that said functions might be an effective diagnostic index for reproductive performance. Therefore, the production of oxytocin-induced prostaglandin F_2α and epidermal growth factor in bovine endometrium, such as the physiological reaction in vivo, may be useful in detecting repeat breeder cows. Although the diagnosis is possible using relatively simple techniques such as biopsy, culture, and hormone assay, it is difficult to apply such diagnosis to the field conditions. However, further improvements in the exhaustive gene expression analysis of uterine function in repeat breeder or low fertility cows, so as to determine the genes associated with physiological reactions, could lead to new diagnostic indexes resulting in improved reproductive efficiency.