Objective To evaluate the clinical diagnosis and treatment of acute renal infarction.Methods Two cases (3 sides) of acute renal infarction were reported.The patients were 1 male and 1 female,with the age of 62 and 54 years.Case 1 presented acute left flank pain,and enhanced CT showed a non-enhanced area in the upper and mid pole of the left kidney.The diagnosis of focal renal infarction was made and treated with low-molecular heparin (6000 U ).Case 2 presented acute both right abdominal and flank pain,and enhanced CT showed right renal artery embolism and right renal complete infarction.Digital subtraction angiography (DSA) and catheter thrombolytic therapy was applied.4 months later,the patient presented acute left flank pain,and enhanced CT showed a low density area in left kidney without enhanced by contrast,and DSA and catheter thrombolytic therapy was applied again.Results In case 1,contrastenhanced MRI showed a still low signal area like enhanced CT after 2 days of treatment.The renal function remained normal in the follow-up of 36 months.In case 2,the right kidney resorted to moderate blood flow but became atrophy later.In the follow-up of 4 months,a recurrent focal infarction was confirmed in left kidney by enhanced CT.The left kidney also resorted to moderate bloodflow after DSA and catheter thrombolytic therapy.The renal function became normal after follow-up of 10 months and no new infarction was observed.Conclusions The diagnosis of acute renal infraction could be made by enhanced CT or MRI.Early diagnosis and location of the infraction renal artery is critical for recovery of the impaired renal function.Acute renal infraction should be suspected in patients with unexplained persistent and steady flank or abdominal pain in emergence department.