143 patients with Hodgkin's disease stage III (65 PS III, 78 CS III) were treated with radiotherapy alone (33 patients), combination chemotherapy alone (56 patients), or radiotherapy plus combination chemotherapy (54 patients). They were followed till death or from 7 to 191 months. Prognostic factors including treatment, peripheral + intrathoracic tumour burden (assessed by combining tumour size in each involved region with number of involved regions), intraabdominal tumour burden (assessed by combining size of lymphographically involved lymph nodes in each region with number of lymphographically involved regions), histologic subtype, B-symptoms, number of involved regions, mediastinal involvement, pretreatment ESR, sex, age, laparotomy, and substage were examined in multivariate analysis. With regard to disease-free survival, total tumour burden (intraabdominal and peripheral + intrathoracic) emerged as the only pre-treatment factor of independent prognostic significance. With regard to overall survival the only factor of independent significance apart from age turned out to be intraabdominal tumour burden. The results of the present study thus support recently published findings regarding early stage disease to the effect that tumour burden is the single most important prognostic factor in Hodgkin's disease.