Renal infarction is a rare disease which must be considered in any case of low back pain. The most frequent causes are related to emboligenic heart disease, renal artery fibrodysplasia or trauma. The authors report the second published case of idiopathic renal infarction. The diagnosis is usually suggested by contrast-enhanced abdominal CT scan, but is confirmed and refined by selective renal arteriography or CT angiography. Treatment may be medical or surgical depending on the severity of the lesions and the patient's general state. The therapeutic indications are discussed in the light of a review of the literature.