The effect of beta-carotene on the fertility and milk progesterone level of dairy cows was studied through the oral administration of 600 mg/ cow/day of a patent preparation of beta-carotene for a period of 3 months. Four (80%) of the five experimental cows conceived and proved to be pregnant, following the consumption of the preparation. The Radio immunoassay (RIA) of the milk progesterone revealed the presence of a significant (P/ 0.005) increase of the hormone level after the intake of beta-carotene. A significant (P/ 0.005) increase of milk progesterone level was also observed in the pregnant than non-pregnant cows with values of 19.075+2.139 ng/ml and 6.27+1.5 ng/ml respectively.