On the basis of a case of partial nephrectomy of a single functioning kidney performed with immediate success in a 77-year-old woman, the author reviews the main data from the literature concerning this particular treatment of carcinoma of the kidney. In the great majority of cases the carcinoma required partial nephrectomy only because the affected kidney was single. Operative mortality was low : 2.6 %. Three year survival is 61 % of cases and it is important to note that terminal renal failure and recurrences in the remaining portion of the kidney are rare. Metastases represent the chief cause of death. Survivals ranging from 6 to 14 years have been reported. When the fact that the kidney is single is not because of nephrectomy for a carcinoma, the prognosis after partial nephrectomy is the same as that after wide excision for carcinoma (in patients with both kidneys). When the opposite kidney had been the site of a carcinoma and even more so in the presence of metastases, the prognosis becomes far less good. With a single kidney, the development of a carcinoma does not necessarily imply the need for total excision of the kidney followed by intermittent haemodialysis. A partial nephrectomy is worth the attempt when it appears to be reasonable. A number of particular technical features are emphasised : - the need for prior arteriography which defines the respective topography of the tumour and the renal vessels, - the safety of temporary clamping of the renal artery when the kidney is made hypothermic by cooling using ice piled up in contact with the kidney, - the possibility of performing such an excision in situ via an appropriate surgical approach.