Theeffect of Mediterranean mussel shell (Mytilus galloprovincialis) (MMS) onperformance, egg quality and some blood parameters were studied on quails(Coturnix coturnix Japonica) for a period of 10 weeks (13-23 weeks). A total of90 quails were randomly separated into one control and two treatment groups.Each group was divided into six subgroups, each containing 5 animals. MMS wasreplaced with lime stone at the ratios of 50 and 100% in first (50% MMS) andsecond (100% MMS) group rations respectively. The diets were prepared to beisocaloric and isonitrogenous. Rations and water were given ad libitum. Casource replacement did not significantly affect body weight, egg weight, eggyield, feed intake and feed conversion ratio of laying quails. The effects ofMMS replacement on shape index, yolk index, yolk color, blood Ca, Mg, P levelswith Mg and P levels of egg shell had no significance. Ca levels of egg shelldecreased (p<0.05) in treatment groups however, the amount of crude ash oftibia was not altered. In sum, dietary MMS did not alter egg quality of layingquails. It may be concluded that MMS can be replaced with limestone in the dietof laying quails.