This study was conducted to investigate the effects of dietary dried baker's yeast on laying performance, egg traits and some blood parameters of quails. In the experiment a total of 342 Japanese quails (Coturnix coturnix japonica) aged ten weeks were equally divided into six groups of 57 (three replicates of 19 quails each). Six levels (0, 4, 8, 12, 16 and 20%) of dried baker's yeast were included in isonitrogenous and isocaloric diets. The experimental period lasted 14 weeks. At the end of the experiment, there were no significant differences among the groups in body weight, feed intake, protein intake, egg production, feed efficiency, egg yolk index and egg haugh unit. Blood serum levels of total protein, triglyceride and cholesterol were not affected by dietary dried baker's yeast. Diets containing 4 and 8% of dried baker's yeast increased the egg weight significantly (p<0.01). The inclusion of dried baker's yeast at the level of 20% to the diets reduced egg shell thickness and egg albumen height. It is concluded that dried baker's yeast can be used up to 16% in the diets of laying quails without adverse effects on the measured parameters. © 2008 Springer Science+Business Media B.V.