The purpose of this research is to investigate the effects of nitrate as a calcium appearance on the hepatic and renal histology. Iraqi fertilizer firm in supplied the calcium nitrate tetrahydrate was used in this study. Twenty-four male albino wistar rats weighing 220 ± 25 g were kept under conditions of natural photoperiod, humidity 50±10%, and temperature 25±2° C. These were divided into 3 groups: G1 control group, G2 received 200 mg/kg, G3 received 400 mg/kg. Rats were administered calcium nitrates orally for thirty days after the salts were dissolved in mineral water. Animals were then sacrificed by being beheaded in the neck region. Organs such as the kidneys and liver were taken for histological analysis. Liver and kidney samples were taken from rats that were given varying amounts of calcium nitrate for a duration of 30 days. The liver sections showed regular histological architecture with hexagonal lobules and visible capillary sinusoids. The livers of the 200 mg/kg group showed mild histological damage, while the 400 mg/kg doses showed significant vascular dilatation, congestion, hepatocyte degeneration, bleeding, and lipid vacuolation. The kidneys showed severe histopathological changes, including glomerular atrophy, intra-glomerular hemorrhage, and vascular congestion, compared to the G2 which showed mild renal lesions. In conclusion, nitrate induced significant alterations in the kidneys and liver architecture that were dose-dependent. Finally, greater dosages of calcium nitrate used excessively might be harmful to humans and other mammals.