Vitamin Bi 2 is a member of the vitamin B complex. It contains cobalt, and is also known as cobalamin. It is exclusively synthesised by bacteria and is found primarily in fish, meat, poultry, eggs, milk and milk products. Vitamin B 1 2 deficiency have an underlying stomach or intestinal disorder that limits the absorption of vitamin Bi2 and might be caused to megaloblastic anemia. In this study cow milk samples were collected from in two different region in Turkey. In milk samples the amount of vitamin B 1 2 was detected by using ELISA. The vitamin B 1 2 concentrations of milk samples obtained from the cows of Holstein, Jersey, Zavot and East Anatolian Red species were determined as 0.98ug/L, 1.15ug/L, 2.93ug/L and 1.56ug/L, respectively. The concentrations of vitamin B 1 2 in Zavot cows milk were higher than the other species.