This study has been carried out to investigate that the effect of different levels of in ovo zinc, manganese and copper mineral mix injection on the hatchability and some tissue characteristics in the Japanese quail breeder eggs. In the study a total 400 Japanese quail breeder eggs which have similar weight have been randomly distributed to four different experimental groups: C as control non-injected (C), MinMix1 has been injected with 15+15+3 µg Zn-Mn-Cu mineral mix + 0.2 ml physiological serum per egg, MinMix2 has been injected with 30+30+6 µg Zn-Mn-Cu mineral mix + 0.2 ml physiological serum per egg and MinMix3 has been injected with 45+45+9 µg Zn-Mn-Cu mineral mix + 0.2 ml physiological serum per egg. The effect of treatment on hatchability, hatching weight and tibia weight, leg, beak and tibia lengths has been found to be unimportant. The yolk sac weight was lower in the injected groups compared to the control group, whereas the heart and liver weights, chick and wing lengths have significantly increased with the in ovo mineral mix injection. The hatching of chicks in the injected groups has started earlier than the control group and the hatchings of these groups were completed earlier, except for the MinMix3 group. These results demonstrated that in ovo injection with MinMix2 increased heart and liver weights and chick and wing lengths while in ovo mineral injection decreased yolk sac.