LH/hCG receptor has been found in extragonadal tissues in human and animals. The myometrium presents such receptors but their functional role is still not clear. Aim of our study was to test the activity of human chorionic gonadotropin (hCG) on bovine uterine contractility. Uterine strips from cows both during follicular and luteal phases were mounted in an organ bath and then exposed to increased doses of hCG. The amplitude of the myometrium contractions were significantly decreased in the follicular and luteal phase but the frequency was not affected. These findings prove a relaxing effect of hCG in the bovine uterus, as already shown in the sow and human, and its possible functional role in modulating uterine contractility.