Bovine gangrenous mastitis is an acute or peracute condition involving 1 or more quarters of the cows udder. It occurs infrequently, but mortality is high. It has been claimed that the ligation of the mammary vessels retards systemic absorption of toxins produced in the gangrenous tissue mass, and it greatly hastens sloughing of affected tissues and therefore total healing time is subsequently reduced. This study was arranged to compare the ligation method with other methods of mastectomy. 18 cows were randomly divided into four groups, and using local anaesthesia method, four surgical techniques were performed and compared as follows: In the group 1, the external pudendal artery and vein on either side were ligated and transected. The external pudendal artery and vein, perineal artery and vein and the milk vein were ligated and transected, in group 2. Complete mastectomy was performed with the cows in dorsal recumbency in group 3. In the group 4 the external pudendal artery and vein were ligated similarly to the first group and complete mastectomy was performed 8 +/- 2 days later similarly to the third group. Following the operation the animals were under close observation and daily clinical assessment. The results indicated that: the mammary tissue did not slough in any cases of the group 1 except sloughing of a piece of skin (25x10 cm) on the right lateral aspect of mammary gland in one cow. In the group 2 with ligation of all mammary vessels, only in one case the mammary skin on either side of the gland was sloughed which was regenerated later. Two cows from group 3 died 15 days following the operation due to uncontrollable infection of the surgical site. Group 4 which had ligation of vessels first and mastectomy later; due to development of collateral circulation from the rectus abdominis muscle and enlargement of perineal arteries showed severe haemorrhage during operation and had longer operative time compared to the simple mastectomy group. Due to prolonged operative time, one cow from this group developed permanent left radial nerve paralysis and downer cow syndrome and one cow died a day later due to severe blood loss. Therefore it was concluded that ligation of vessels of the mammary gland is not helpful either for sloughing of mammary tissue or reduction of mammary circulation. Complete mastectomy is recommended in exceptional circumstances following conservative therapy with the animals in good physical conditions.