Based on the Swiss Pediatric Oncology Group (SPOG) cancer registry data during 1981-1991, a high average incidence of 8 new NHL per million children younger than 15 years per year was found. Of 162 children with NHL registered in 1976-1991, 120 were study patients, i.e., officially registered and treated according to SPOG or Pediatric Oncology Group (POG) protocols, while 42 were non-study patients, i.e., patients not officially enrolled on protocols. Overall, 91 of 120 (76%) study patients remained alive. Seventy-nine study patients were treated according to older SPOG protocols, and 53 (67%) of these survived, while 38 of 41 (93%) study patients treated according to newer POG protocols remained alive (P = 0.0068). Only 22 (52%) of the 42 non-study patients survived (P = 0.0001). There was no improvement if the survival of non-study patients before and since 1986 was compared. Population-based treatment results in Switzerland were similar to those in the United Kingdom. They provided an important base for the development of future treatment strategies.