An experiment was conducted to study the effect of metabolizable energy (ME) and protein of Japanese quails diets on offspring performance and antibody production against sheep red blood cell (SRBC). A total of 432 Japanese quails (13 week-old) were divided into nine treatments. Each treatment comprised four replicates of twelve birds (9 female and 3 male). Nine diets including three levels of metabolizable energy (2750, 2900 and 3050 kcal ME/kg diet) each at three levels of crude protein (18, 20 and 22% CP/kg) in a 3 × 3 factorial design were formulated. Offspring live weight was significantly lower in week 1, 2, 3 and through the whole of growth period when quails fed diets contained 2750 kcal/kg energy and 18% protein. Quail feeding with different levels of energy and protein did not affect feed intake of offspring. The feed conversion ratio of offspring was significantly higher when quails fed diet with 2750 kcal/kg ME and 18% protein during the experimental periods. Quail fed diet containing 2750 kcal/kg ME with 18 and 20% protein decreased antibody production of offspring against SRBC. It was concluded that using 2750 kcal/kg energy with 18 and 20% protein in diets of quails may have adverse effects on offspring growth rates and immune responses. Manuscript profile