Acute renal failure (ARF) is a sudden, sharp decline in the function of kidneys as a result of an acute toxic or inadequate oxygen supply to the kidneys. Abnormality in complete blood count parameters occur in kidney failure. The aim of the present study is to correlate blood count parameters with serum urea and creatinine in acute renal failure patients.Spearman’s rho correlation was used to correlate hemoglobin, neutrophils, lymphocyte and basophil levels with serum urea and creatinine in which hemoglobin was estimated by photometric method, lymphocytes, neutrophils and basophils by VCS Technology by Beckman Coulter and urea and creatinine by the Roche Cobas 6000 autoanalyser. This study included 102 diagnosed ARF cases taken from nephrology ward of Kasturba Hospital, Maniple. Our study showed decline in hemoglobin levels in ARF patients. This decline in hemoglobin levels may be due to decreased production of erythropoietin in ARF cases. A positive correlation of neutrophils with urea in ARF cases may be due to ischemia and inflammation in the kidneys leading to enhanced retention of toxic substances. As a result we can conclude that complete blood count parameters play a significant role in the pathophysiology of ARF cases.