From 1982 to 1989, 68 patients with Stages IA to IIIB Hodgkin's disease were treated by simultaneous supra- and infradiaphragmatic irradiation (SSI-RT). 46 patients received exclusive radiotherapy for Stages IA and IIA (extended mantle field irradiation (EMF) 31, and total lymphatic irradiation (TLI) 15). Combined modality treatment including pre-irradiation chemotherapy, was given to 22 patients (CH-EMF 12 and CH-TLI 10). The median follow-up was 64 months. 5-year overall survival was 94% in combined Stages IA and IIA, and 100% in Stage IIIA. 5-year freedom from relapse was 87% in combined Stages IA and IIA, and 80% in Stage IIIA. Toxicity was evaluated in 64 patients. Acute and long term toxicity was similar to previously reported data on sequential supra- and infradiaphragmatic irradiation. In SSI-RT prior chemotherapy affected pre-irradiation blood counts and was associated with delayed post-irradiation haematological recovery. The relative mean white blood cell (WBC) decrease ranged from 47% (EMF) to 61% (TLI). The mean platelet decrease ranged from 43% (EMF) to 80% (CH-TLI). Both prior chemotherapy and total lymphoid irradiation increased haematotoxicity. The mean duration of breaks ranged from 3.9 days in EMF to 14.9 days in CH-TLI. The mean treatment time, ranging from 43 days in EMF to 54 days in TLI, was significantly shorter than in sequential schedules (up to 112 days). Our results indicate that SSI-RT is an effective and safe treatment. Its use seems to be limited mainly by prior chemotherapy. As compared to sequential schedules, the risk of match line overlap is avoided, overall treatment time is decreased, and treatment costs are minimized.