Primary renal lymphoma is a controversial entity. Only 29 cases have been reported since 1980. Diagnostic criteria are not well established. We report here 3 new cases and review the literature. Primary renal lymphoma was considered on the basis of uni- or bilateral nonobstructive nephromegaly with or without renal failure. In all cases, the diagnosis was made after renal biopsy. Extrarenal abdominal involvement was excluded by imaging techniques. The role of staging laparotomy remains controversial. Chemotherapy is the treatment of choice, but the prognosis is poor. We propose a clinical definition of primary renal lymphoma in order to achieve a better management of the disease.