142 patients with Bell’s palsy were monitored by repeated applications of evoked EMG. Detailed and objective information as to the incidence, degree, and progression of denervation in Bell’s palsy was presented. Various degrees of denervation were found in 53 patients (37%). A very rapid ‘fulminant’ development of pronounced denervation was confirmed in 20 patients. A late but slow ‘creeping’ development of pronounced denervation was proved in three patients. The rest of the patients showed slight or moderate denervation with no further increase in denervation.