: In chronic renal failure there is a steady and continued decrease in renal clearance or glomerular filtration rate (GFR), which leads to the gathering of urea, creatinine and other waste metabolites in the blood. Haemodialysis is considered as a good therapeutic option in the context of the renal replacement therapies in which different body waste products including urea, creatinine and free water are removed from the blood. In view of that, the present study was conducted to evaluate the effect of haemodialysis on different renal biochemical parameter in CRF patients.The present study was a hospital based study including 84 chronic renal failure patients on haemodialysis attending a tertiary care hospital in Bihar. Blood samples were collected before and four hours after haemodialysis and serum urea, creatinine, uric acid, potassium, sodium and calcium were estimated.Our results revealed that there was significant decrease in the serum level of urea, creatinine, uric acid and potassium in post dialysis samples with p-value (<0.001, 0.001 0.003 and 0.001) respectively when compared to pre dialysis samples, while showed significant increase of sodium and calcium level in post dialysis samples with p-value (<0.004 and 0.005)The Study concludes that, haemodialysis increase serum sodium and calcium level and decrease serum urea, creatinine, uric acid and potassium level.