The aim of the study was to identify all patients with poor risk Hodgkin's disease (HD) using a numerical prognostic index in a defined population and to recruit them into a trial of intensive chemotherapy prednisolone, vinblastine, doxorubicin, chlorambucil, etoposide, bleomycin, vincristine, procarbazine (PVACE-BOP)x3+autotransplant (Arm A) versus PVACE-BOPx5 (Arm B) in first remission. In 10 years, the Scotland and Newcastle Lymphoma Group (SNLG) registered 930 patients with HD of whom 178 (19%) were identified as 'poor risk' by the SNLG index and were aged 16-59 years. 126/178 (71%) entered the study. Of the 120 confirmed poor risk HD cases, all completed PVACE-BOPx3 with a 93% Complete Response/unconfirmed Complete Response (CR/CRu) rate. Only 65/107 in CR accepted the randomisation. With a median follow-up of 6 years, both arms of the trial have a similar time to treatment failure (TTF) (Arm A 79%+/-11 versus 85%+/-7 Arm B, P=0.35). Advanced stage 'good risk' patients not included in the trial receiving standard therapy with CLVPP or ABVD had a 75% 5-year survival. The study demonstrates that PVACE-BOP therapy in the poorest risk group (58% had an IPI>/=3) produces excellent CR rates (93%) and overall survival with minimal toxicity, and that the substitution of autotransplant in first CR does not improve outcome. The use of the objective SNLG index accurately helped in the selection of the poorest risk group in this population study. The placing of a randomised control trial within the context of a population-based study of HD enhances the validity of the outcome.