Two consecutive treatment protocols, NHL-89 and NHL-96, for pediatric diffuse large cell lymphoma (DLC) and lymphoblastic lymphoma (LBL) were conducted between March 1989 and December 2004 by Kyushu-Yamaguchi Children's Cancer Study Group. Forty-two patients (DLC: 15, LBL: 27) and 34 patients (DLC: 8, LBL: 26) were enrolled in NHL-89 and NHL-96, respectively. DLC patients received induction therapy of high-dose methotrexate (MTX) followed by repeated administration of intermediate MTX. LBL patients received a 4-drug induction followed by intensification, consolidation with cranial radiotherapy (15 to 24Gy), and maintenance. The maintenance phase consisted of multiple drug treatment; including prednisolone, vincristine, cyclophosphamide, and 6-mercaptopurine. With a median follow-up of 150 months for NHL-89 and 90.5 months for NHL-96, the estimated event-free survival at 5 years are 76.2±6.6% and 67.7±8.0%, respectively. Both studies improved the prognosis of DLC and LBL over our previous study of NHL-858.