Oxytocin is known as the milk ejection hormone, but suckling increases plasma levels of both vasopressin and oxytocin in the goat and intravenous infusions of vasopressin increased milk flow and milk fat content in goats. The effect could be a result of vasopressin binding to the oxytocin receptor. The aim of the present study was, therefore, to investigate if injection of vasopressin causes milk ejection in the goat. Eight lactating goats were separated from their twin kids between 6.30 h – 14.00 h and hand milked twice daily. At each milking the milk stored in the large cistern in the udder was collected first, then there was a 2-min interval after which the residual milk was taken out. On treatment days, the goats were hand milked to empty the cisternal milk reservoir in the udder and then vasopressin (125 ng) or oxytocin (8 ìg) was injected into the jugular vein. Two minutes after the injection the goats were milked to get out the residual milk. Three blood samples were collected from the contralateral vein before milking, after milking, and after injection of oxytocin or vasopressin. Without hormone injections the residual milk volume was 12 ± 7 g, after oxytocin injections 118 ± 36 g (P <0.001) and after vasopressin injections 36 ± 18 g (P<0.01). The fat content was significantly elevated in the residual milk after oxytocin (P<0.001) compared to control days but not after vasopressin injections. In conclusion, vasopressin injections increased the amount of residual milk, but the effect was much smaller than after oxytocin. This is consistent with the idea that vasopressin may exert its effect via the oxytocin receptor, but with less efficiency than the oxytocin itself.