The main aim of this research was to assess the effect of intake flaxseed oil on kidney failure rats by measured kidney functions .Twenty-four  adult male albino rats, weighting 166g±10 were divided randomly into four  groups, each group had six rats. All animals were given libitum standard diet. 6 rats were left as negative control (Group 1), the remain 18 rats were injected with diclofenac Sodium a dose of (100 mg/kg) for 3 days then divided randomly into equal 3 groups as following: Control positive group (C+) fed on standard diet only (Group 2), kidney failure rats fed on 2% flax seed oil from fat meal enteric injection (Group3), kidney failure rats fed on 10% flax seed oil from fat meal by enteric injection (Group4). During the experimental period for 5 weeks, the feed intake was recorded every day and body weight every week. At the end of the experiment, blood samples were collected and hemoglobin, platelets, relative weight of internal organs, kidney and liver functions, as well as histological tests of the kidneys and liver were done. The results showed a significant improvement in all experimental groups compared with the control group. Rats that fed on the flaxseed oil, noticed a significant decrease in the relative weight of the liver, kidney, heart, lungs, and brain as compared with the positive control group. The lowest level of urea, uric acid, creatinine was observed in the group of rats that fed on 10% flaxseed oil. Furthermore, a non-significant decrease in both ALT and AST in blood serum in the group that fed on 10% flaxseed oil compared with positive control group. Total protein and albumin levels were non-significantly higher in the group fed on 10% flaxseed oil. Finally, the results revealed that feeding flaxseed oil 10% improved kidney functions significantly, and we can recommend the using of flaxseed oil in food products because due to its health benefits.