Brachial plexus neuropathy is an unfortunate complication that sometimes follows radiotherapy to the axillary and supraclavicular regions. A patient is described who, 30 years after radiotherapy for Hodgkin's disease and more than 10 years after the development of radiation-induced bilateral brachial plexus neuropathy, presented with bilateral diaphragmatic weakness secondary to bilateral phrenic nerve weakness. Previous radiotherapy was the most probable cause of the condition.