The objectives of the present study were to validate transrectal ultrasonography (US) as a reliable diagnostic tool for endometritis, as well as to determine the efficiency of intrauterine infusion (IU) of benzathine cephapirin plus systemic PGF2α as a treatment protocol of endometritis in Holstein dairy cows. 260 Holstein cows were included in this study. The affected cows were examined rectally and US. The cows were divided according to the diagnostic method and treatment protocol into 3 groups. Group1: rectally diagnosed and received systemic PGF2α. Group2: rectally diagnosed and received IU benzathine cephapirin plus systemic PGF2α. Group3: US diagnosed and received IU benzathine cephapirin plus systemic PGF2α. Good reproductive indices were recorded for cows examined US and treated with combination of IU benzathine cephapirin plus systemic PGF2α. A highly significant positive correlations were observed between days in milking (DIM) and most of tested reproductive indices. Meanwhile, Daily milk yield was negatively correlated with all tested reproductive indices. In conclusion, trans-rectal US could be used as a reliable method for early diagnosis of endometritis. In addition, using a combination of IU application of benzathine cephapirin plus systemic PGF2α was superior treatment protocol in endometritis in comparison with PGF2α.