The objective of the present study was to evaluate the inclusion of corn oil in the diet of sheep and its eect on serum levels of progesterone and estradiol, Twenty-one Pelibuey sheeps were divided into three treatments based on the level of oil included in the diet (T0 = 0, T3 = 3 and T6 = 6% respectively, on dry basis). Blood samples were obtained to determine hormones in serum. Cholesterol and progesterone were higher for T3 and T6 treatments (p < 0.05) compared to T0. Insulin was higher (p < 0.05) in the T6 treatment compared to treatments T3 and T0. At the time of ovulation, estradiol concentration was higher (p < 0.05) for treatments T3 and T6 compared to T0. The inclusion of corn oil in the diet increases the levels of cholesterol, progesterone, estradiol and insulin in sheep hair.