The aim of this research is to evaluate by ultrasound diagnosis foetal degeneration and total uterine involution in pharmacological induced abortion of the bitch with subcutaneous injections of cloprostenol associated to cabergoline administration per os. 40 bitches of different breed were subjected only after pregnancy ultrasonographic diagnosis executed during the 3rd week after an unwanted mating. The Pg F2a administration was stopped when the ultrasound monitoring confirmed the foetal death, thus to decrease the total amount of the drug, to make practically void the secondary effects and not to interfere with the uterine involution.