Abstract: A method of vaccinating a cow against mastitis by administering to the cow an intravaginal anti--mastitis vaccine during the lactation period followed by administering an intracisternal anti-mastitis vaccine to the cow during the dry period. The intravaginal and intracisternal vaccines preferably contain Toxoided Alpha-Toxin, detoxified Leucocidin and an extract of the bacteria Staphylococcus aureus.