ObjectivePrimary renal lymphoma is one of the malignant lymphomas that initially presents in the extra lymphonode, which is rarely seen in children．This study reported two cases of primary renal lymphoma in children who were definitively diagnosed by renal biopsy. Renal tubular acidosis was the initial manifestation in both cases. They were referred to the hospital with chief complaints of polydipsia, polyuria, debilitation, vomiting and anemia. Imaging and laboratory examinations showed bilateral renomegaly, hypocalcemia, hypophosphatemia, and metabolic acidosis. One of the patients discontinued therapy. The other received chemotherapy including prednisone, vincristine, cytarabine and L-asparaginase, combined with intrathecal injections of methotrexate, dexamethasone and Ara-C and supporting treatment. Twenty-three days after treatment, polydipsia and polyuria were relieved, and acidosis, kaliopenia and anemia were improved in the patient. There were no abnormal findings in the renal B-ultrasound re-examination. It was concluded that when a patient is suspected of renal lymphoma, diagnostic puncture and renal biopsy should be performed early. Early combined therapeutics including chemotherapy, radiation therapy, surgery and supporting treatments may result in a favorable prognosis in patients with this disease.