Clinico-pathological details are given of a patient who survived bilateral renal cortical necrosis for 44 days as a result of treatment by haemodialysis. Cortical calcification was demonstrable radiologically in life and at necropsy. The literature pertaining to renal ischaemic damage and calcification is reviewed. Conclusions are drawn as to the mechanism that produces renal cortical calcification in the light of previous experimental work and the study of the present case. It is suggested that the widespread use of haemodialysis in treatment is likely to result in the detection of an increasing number of such cases.