This experiment was carried out to determine the effects of different levels of yeast culture (Saccharomyces cerevisiae) supplementation to the broiler turkey diets on the performance characteristics, some blood parameters and immune system. A total of 48 female poults aged five weeks were divided into one control group and three treatment groups each containing 12 female poults. The diets of the first, second and third treatment groups were supplemented with 1, 2 and 3 g/kg yeast culture (Diamond V "XP", Saccharomyces cerevisiae), respectively. The experimental period lasted 10 weeks. At the end of the experiment body weight, body weight gain, feed consumption, feed efficiency, carcass yield, weights and rates of internal organs, abdominal fat and the values of pH and viscosity of small intestine of turkeys were not significantly affected by different levels of yeast culture. There were no significant differences among the groups in total protein, cholesterol, triglyceride, uric acid, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase of blood serum and haemetological parameters. Immune system of turkeys was also not affected by dietary yeast culture. The results in this study demonstrated that yeast culture (Saccharomyces cerevisiae) supplementation at the levels of 1, 2 and 3 g/kg to the diets of female broiler turkeys did not have any significant effects on performance characteristics, some blood parameters and immune system.