Nonketotic hyperglycemia has a definite convulsive effect, which may manifest itself in generalized or focal seizures. This report deals specifically with focal convulsive phenomena. Two patients with nonketotic hyperglycemia focal seizures are described. Focal seizures are of motor Jackson, aphasic, adversive or of the 'epilepsia partialis continua' type. Different types of focal seizures may appear in one and the same patient. Focal epilepsy can be the first manifestation of a diabetic disorder. Focal epileptic seizures are linked with moderate nonketotic hyperglycemia with values of 360 mg% sugar and 310 osm. Higher values lead to generalized seizures and coma. The mechanisms are discussed and pertinent literature is reviewed.