AIM:To investigate the relationships between angiotensin converting enzyme gene polymorphism and lacunar infarction in patients with essential hypertension.METHODS:Polymerase chain reaction(PCR) was used to determine the genotypes for an insertion/deletion polymorphism of 287 pb fragment of ACE gene in 50 healthy persons,50 patients with simple essential hypertension and 30 patients with essential hypertension and lacunar infarction.RESULTS:There was no significant difference of genotype and allele between healthy persons and patients with simple essential hypertension;but there was significant difference of D allele and DD genotype of ACE gene between esential hypertensive patients with lacunar infarction and patients with simple essential hypertension and healthy persons.CONCLUSION:There is a significant relation between ACE gene polymorphism and essential hypertensive patients with lacunar infarction.