A high frequency of diabetes mellitus is reported in a series of 130 patients presenting with Bell's palsy. The frequency was 45% at age ten to nineteen, and increased with age, the frequency for the whole series being 66%. Most of the patients had no other evidence of diabetic neuropathy. It is suggested that Bell's palsy is a syndrome resulting from ischæmia of the facial nerve, in many cases perhaps due to diabetic angiopathy. Vasoconstriction, sludging, and thrombosis may also be considered. Bell's palsy may be the first manifestation of diabetes, and in any patient presenting with this neurological deficit, glucose tolerance should be checked.