Forty Japanese quails of both sexes ranging from 1- 45 days old were used to elucidate the gross and structural changes in the liver during the post-hatching period. The liver of quails develops at a slower rate than the body cavity. In one day old birds, it occupies most of the cranial part of the body cavity and extends caudal to the sternal crest, but by advancement of age it moves cranially to become completely hidden by the sternal crest in mature birds. The liver of newly hatched quails consists of right and left lobes that are equal in length. The relative development of the left lobe is less active, so that in mature birds, it is shorter and smaller than the right one. Two intermediate lobes are also recognized at one day old, but the left one develops at a slower rate, so it becomes smaller than the right one at 30-45 days old. Structurally, the liver of newly hatched quails is markedly immature. There are few portal triads and central veins, which occupy 8.17% of hepatic tissue. The hepatocytes are not yet arranged in cords. By advancement of age, the portal triads and central veins increase in number and occupy 11.2% of hepatic tissue, the hepatocytes become arranged in cords with intervening sinusoidal network in premature and mature quails. The nucleus/cell percentage of the hepatocytes decreases during the post-hatching period that may reflect an increase in function. The hepatocytes of newly hatched quails contain large quantities of fat, which decrease to a minimal amount at 15 days old, then reincrease in premature and mature birds. However traces of glycogen are demonstrated in the hepatocytes of newly hatched birds, which increase toward the mature stage. In conclusion, the liver of quails surpasses obvious post-hatching changes not only grossly but also structurally indicating structural and functional hepatic maturation during this period.