An inquiry was made into the clinical practice and paraplegia rate associated with operations for coarctation of the aorta conducted by surgeons in the United Kingdom and Ireland. Paraplegia occurred in 16 patients in a total of 5492 operations, an incidence of 0.3%, or once in 343 operations. The aetiology and measures that may be taken to avoid this complication are discussed. The medicolegal consequences need no emphasis and it is recommended that finger palpation alone as a method of assessing the adequacy of distal aortic pressure should be abandoned in favour of continuous electromanometric visual display of the aortic pressure in all patients. In the long term, serious consideration must be given to developing spinal cord monitoring using somatosensory evoked potentials.