Methionine is an essential amino acid. When the metabolic pathway of methionine are interrupted, Homocysteine (Hcy) level will be elevated ,and this elevation is pathogenic. Folic acid can effectively reduce blood Hcy levels. The thirty adult male rats were randomly divided in to three equal groups and were treated daily as follows for 42 days. first (T1) served as control group. Rats of the second group (T2) were intubated orally 100 mg / kg B.W. of methionine . rats of the third group (T3) were intubated same doses of methionine plus 5mg of folic acid supplementation . Fasting blood samples were collected at 21, and 42 days of experiment to study the following parameters: Serum creatinine (SC) concentration, Blood urea nitrogen (BUN) concentration and Serum uric acid (SUA) concentration . Furthermore; section of kidney was assessed for histopathological studies. The resulted revealed significant increase (P< 0.05)of methionine group in SC , BUN and SUA concentrations in 12 , 42 day of treatment as comparing to control (T1). On the other hand that animals treated with folic acid plus methionine (T3) showed significant decline in SC , BUN and SUA concentrations in 42 day of treatment . Histological section of rat kidney received methionine showed monocyte cells around collected renal tubules ,while folic acid supplementation in groups T3caused regression of renal damage induced by methionine. It seems that methionine was effective in induction of oxidative stress and change in some biological markers related to kidney disease. Also it seems that folic acid exert protective actions against the damaging effect of methionine.