Three groups of Japanese quails were reared on diets differing in protein content, which was 28, 24 and 20% in successive rearing stages in group I, whereas in group II it was lowered, to 25, 22 and 19%, respectively, and in group III, to 22, 20 and 18%. It was found that the protein level did not affect the morphological traits of eggs or the protein percentage in their content; however, fat and ash quantities increased. Yolk cholesterol and chemical composition of egg yolk and white were at similar levels in all groups. Improvement of fertilization rate, but lowering of hatchability, was found in groups fed low-protein diets.