Magnetic transcranial stimulation was used in 90 subjects (60 acute ischaemic sylvian strokes and 30 healthy controls) in order to evaluate the clinical value of the excitation threshold (ET) in the estimation of functional prognosis. ET mean values recorded 7, 30 and 90 days after stroke (at D7, D30 and D90) in two distal muscles of the upper limbs of the patients were compared with results obtained in 30 healthy control subjects. The data from the patients who ultimately achieved a satisfactory functional recovery at D90 were compared with those from patients who had not recovered in that time. Our results suggest that ET evolution differs according to functional outcome: (1) ET mean values were increased in the stroke patients at D7, but ET was constantly lower at D30 and D90 in patients who recovered than in those who did not. (2) ET temporal evolution showed a gradual decrease of the mean values from D7 to D90 in both stroke groups. This ET decrease was more marked in the patients who recovered from D30 to D90, but with only minor change after D30. (3) The localisation of the lesion had no significant effect on ET mean values at D7, D30 or D90. We conclude that the predictive value of ET estimation might be utilised at D30 in patients with ischaemic sylvian strokes.