Abstract: 【Abstract】 Objective To investigate the relationship between gene polymorphism of the plasminogen activator inhibitor-1 (PAI-1) promotor region 4G/5G gene, angiotensin I converting enzyme gene insertion/deletion (I/D) and cerebral stroke. Methods The genotype of 4G/5G allele polymorphism in the PAI-1 promotor region and I/D allele polymorphism in ACE were determined by polymerase chain reaction from leukocytes of 139 normal controls and 203 patients with cerebral stroke. Serum ACE activity was measured by colorimetry, plasma level of PA I-1 activity was determined by spectrophotometric assay. Results The plasma PAI-1 activity (0.769±0.163 AU/mL) and ACE activity in serum (43.42±14.36 U/L) in cerebral ischemia group (CI group) were significantly higher than those in control group (0.652±0.116 AU/mL, 31.28±8.64 U/L, p < 0.01, respectively). The frequency of PAI-1 4G/4G genotype and 4G alleles (43.14% and 62.24%), ACE D/D genotype and D alleles (49.02% and 67.16%) in CI group was significantly higher than those in control group (24.46% and 51.79%; 20.86% and 42.09%, p < 0.05, respectively). However, the difference of these data was not significant between cerebral hemorrhage (CH) and Control group. Furthermore, the effects of PAI-1 4G/4G genotype and ACE D/D genotype on cerebral infarction were synergetic. Conclusion 4G/4G PAI-1 and D/D genotype in ACE may be a susceptible factor to acute cerebral infarction, 4G and D allele homozygous genotype may be the major and synergetic risk factors of acute cerebral infarction.