The relationship between the serum glucose level and the cerebral infarct size, neurological deficits, morbidity outcome, complications and mortality was investigated in 198 acute cerebral infarction patients confirmed by computerized tomography. The results suggested that patients with hyperglycemia had larger infarct size, more neurological deficits, worse morbidity outcome, more complications and higher mortality than their normoglycemic counterparts. Our findings indicated that the elevated blood glucose level in most of the patients with cerebral infarction may be a stress response or a marifestation of latent diabetes. We considered that the hyperglycemia was a factor aggravating cerebral infarction and enhancing the degree of neurological deficit and morphological brain damage. The authors are of the opinion that insulin administration be advised in acute cerebral infarction patients with hyperglycemia so as to prevent further deterioration and improve the outcome.