Review of a very well documented case with a very complete iconography, and of the literature led to the following conclusions. First, it is preferable to treat these patients by a one-stage operation involving nephrectomy on one side and, if possible, conservative treatment to other kidney. Second, that the prognosis in synchronous bilateral renal cancer is much better than that of metachronous bilateral cancers (5-year survival 69% and 37.5% respectively), probably because the former are usually of low grade and early stage. This justifies the most audacious surgical tentatives and, in this respect, this paper is of very high interest.