One hundred and thirty patients with Stage I and II supradiaphragmatic Hodgkin's disease treated with mantle irradiation alone at the Peter MacCallum Hospital, Melbourne between 1968-1977 were analysed retrospectively. The median followup was 7.4 years with a minimum of three years. There were 64 clinically staged (CS) and 66 pathologically staged (PS) patients. The major difference between the two groups was the transdiaphragmatic relapse which occurred in 33% of CS patients, and 7.5% in PS patients. The actuarial five year relapse free survival (RFS) was 48% for CS patients and 67% for PS patients, but the five year overall survival was 90% for both groups, reflecting the impact of salvage treatment. Avid attention must be given to radiotherapy techniques to minimise local treatment failures. High grade nodular sclerosis Hodgkin's disease is associated with poor RFS even after adjustment has been made for stage and constitutional symptoms (p less than 0.003). Further studies will be made on this group of patients who may benefit from combined modality treatment. For PS I and II patients mantle irradiation gives a five year RFS of 67%, thus offering potential for cure in these patients.