One hundred and fourteen untreated patients with pathological stage (PS) IA-IIB supradiaphragmatic Hodgkin's Disease were randomised to mantle radiotherapy alone (55) or mantle radiotherapy followed by 6 courses of adjuvant chemotherapy with mustine, vinblastine, prednisolone and procarbazine- MVPP (59). Patients excluded were those outside the age range 16-65 years and those with massive mediastinal disease precluding laparotomy. Bulk disease was defined as a mass of lymph nodes measuring five centimetres or more in any axis. Mediastinal bulk was present if the ratio of the maximum width of mediastinal disease to the maximal chest diameter was more than one third. All patients achieved a complete remission. Median duration of follow-up was 62 months (range 16-97). The relapse free survival (RFS) was 81%; 69% for radiotherapy alone and 93% for adjuvant chemotherapy (P = 0.002). RFS was also shown to be adversely affected by B symptoms (P = 0.0003), bulk disease (P = 0.018), abnormal CXR (P = 0.037), and increasing stage (P = 0.039). Age, sex, histology, and number of sites involved had no significant effect upon RFS. A Cox multivariate analysis showed that only three variables had a significant adverse effect on RFS - radiotherapy alone, the presence of bulk disease, and B symptoms. The overall 5 year survival was 93% with no statistically significant difference between the two treatment groups (P = 0.54). Survival was adversely affected by three variables - B symptoms (P = 0.02), the presence of bulk disease (P = 0.002), and pathological stage (P = 0.05). High risk groups for relapse are those with bulk and B symptoms. This analysis has shown that RFS was significantly improved by adjuvant chemotherapy, but that overall survival was not.