Monosodium glutamate (MSG) is one of the most widely used food additives as a flavour enhancer but its high dose can induce toxic effects on the liver. Melatonin is a potent antioxidant, could ameliorate acute and chronic hepatic injury. The present work was essentially designed to evaluate the ameliorating role of melatonin on the liver of pregnant female Albino rats and their pups induced by MSG. In the present research, twenty four pregnant Albino rats were divided into four groups (n=6). The control group received saline solution, the melatonin group received 100 mg/kg b.wt, MSG treated group received 400 mg/kg b.wt and ameliorative group received MSG 400 mg/kg b.wt simultaneously with melatonin 100 mg/kg b.wt. All groups were received their corresponding dose from the 4^th day of gestation till the end of weaning period. The histological study of the current work revealed that MSG could induce damage of hepatocytes with cytoplasmic vacuolation, dilation of central vein and blood sinusoids, prominent Kupffer cells, infiltration cells around the portal area, variable degree of fibrosis, and scattered fatty cells. Furthermore, MSG consumption is also associated with ultrastructural alterations that varied considerably from mild structural changes to cytoplasmic lysis and degradation of some cellular organelles. Such alterations were represented by undifferentiated cytoplasm with dispersed vacuoles, nuclear pyknosis, swollen and vacuolated mitochondria, manifested dilated rough endoplasmic reticulum, remarkable aggregation of glycogen granules and fat droplets and obvious dispersion of collagenous fibers. Supplementation of melatonin ameliorated MSG-induced histopathological and ultrastrucural changes in liver cells.