Résumé : Bilateral synchronous multifocal Wilms' tumor is a rare malignancy for which no optimum treatment has been established thus far. The need to preserve renal parenchyma whenever possible is obvious. The authors describe a patient who underwent removal of six subcapsular tumors from a kidney that had been protected from ischemia by in situ cooling with UW-Belzer solution and by surface cooling. This technique was safe, easy to perform, and allowed all the time required to resect the tumors under adequate visual control and to wait for analysis of the frozen sections. It might be a useful alternative to the more complicated "bench" technique. © 1995.