This study investigated the effects of egg shape index and weight on the fertility rate, hatching performance, and hatchability of the Japanese quail. The study was conducted with 3220 quail eggs. The quail eggs were first weighed on precision scales with an accuracy of 0.01 g, after which their width and length was measured with a digital compass. The eggs were then transferred into an incubator by being grouped according to their shape index and weight. At the end of the incubation period, it was observed that eggs with shape index values less than 0.75 and between 0.75-0.85 had higher hatching performance and hatchability than the other groups (P<0.005), while the fertility rate was only low in groups with a shape index above 0.90. An increase in fertility rate, hatching performance, and hatchability was observed for eggs weighing 12 g or more. In conclusion, it was determined that egg shape index and weight have negative correlation on hatching performance.