Endothelin-converting enzyme-1b (ECE-1b) C-338A is a polymorphism located in ECE-1 gene promoter, which has been reported to correlate with the risk of carotid atherosclerosis. We conducted a hospital-based case-control study of 309 patients with ischemic stroke and 309 controls matched on age and gender. The frequencies of ECE-1b-338 CC, CA, and AA genotypes in cases (45.0, 40.4, and 14.6 %) were significantly different from those of controls (53.1, 39.1, and 7.8 %, χ(2) = 8.519, P = 0.014), respectively. Compared with C carriers, A alleles showed correlation with a 42 % increased risk of ischemic stroke (adjusted odds ratio (OR) = 1.42, 95 % CI = 1.11-1.81). After adjustment for potential risk factors, the AA genotype still kept positive correlation with ischemic stroke (OR = 1.78; 95 % CI = 1.06-3.54). In stratified analyses, the significant association of the A allele with ischemic stroke was observed in female subjects (adjusted OR = 1.64, 95 % CI = 1.17-2.89) and the subjects with age ≥ 64 years old (adjusted OR = 2.09, 95 % CI = 1.38-3.23). The present study suggested that the C-338A polymorphism of the ECE-1b gene was associated with an increased risk of ischemic stroke in the Chinese Han population.