The present study aimed to investigate the role of spraying fertilised quail eggs with riboflavin (SP) on hatchability, performance, carcass traits, liver and kidney function, and economic efficiency of growing quail. A total of 260 quail eggs were used for hatching and randomly divided into four treatment groups with five replicates (13 eggs/replicate) in a fully randomised design. The eggs were sprayed with riboflavin before incubation. The groups included a control group (no spraying), and three experimental groups sprayed with 3, 4 or 5 g/l riboflavin, respectively. The spray was applied for 2 min. After hatching, 128 Japanese quail chicks, aged 7 days, were randomly assigned to 4 treatment groups, 32 birds each. The study was conducted over 5 weeks. Compared to the control group, fertility and hatchability rates (%) significantly improved in groups sprayed with 3 g, 4 g, and 5 g of riboflavin (vitamin B2). Quails hatched from eggs sprayed with vitamin B2 showed significant increases in body weight, weight gain, feed intake, feed conversion ratio, and carcass traits at different growth stages compared to the control group. Additionally, all vitamin B2-treated groups demonstrated significant improvements in blood indices. The economic efficiency was also significantly enhanced in treated groups, with the most favourable results observed in the group sprayed with 3 g/l vitamin B2. In conclusion, spraying eggs with riboflavin at varying doses can be recommended to enhance growth performance, blood parameters, carcass traits, and economic efficiency in quails.