Introduction: In India especially in Rajasthan people drink water containing high level of nitrates and concentration up to 500 mg of nitrate ion per liter is not unusual. The ingested nitrate is converted to nitrite in the digestive system and absorb in blood causing methemoglobinemia. Methaemoglobin is not restricted to infants alone but it is prevalent in higher age groups also. The peak of methaemoglobin is observed at 45-95 mg/liter of nitrate concentration of water. Aim of study: To find out the correlation between drinking water nitrate concentration and histopathological changes in esophagus and stomach of rabbits of different groups. Material & Methods: Therefore an experimental study was conducted in 10 rabbits according to guideline of ICMR, New Delhi between three and half month to four months of age having weight ranging 1.310 kg to 10720 kg. Five groups A, B, C, and D & E were formed with two rabbits in each group. The control group A was administered water orally having 06 mg/liter .Group B to E (experimental groups ) were administered water orally having a concentration of 100mg/liter, 200mg/liter, 400mg/liter & 500mg/liter of nitrate respectively for 120 days. Then all rabbits were anaesthetized & sacrificed according to the guidelines of the ICMR and oesophagus and stomach were removed & processed for paraffin sections. Hemotoxyllin and eosin staining was done for microscopic observations. Results: The results showed mononuclear infiltration in the esophagus which started in group B and in stomach, histopathological changes appeared in sub-mucosa, muscularis mucosa , muscularis externa and seosa started from group c. The changes were more pronounced in stomach of group D & E in the form of congestion of blood vessels in sub mucosa and mild infiltration of lymphocytes in muscularis externa.