The role of angiotensin-converting enzyme (ACE) I/D polymorphism in psoriasis have not been determined. Thus, in this study, we aimed to analyse ACE I/D polymorphism for the association with the risk of psoriasis in a Chinese Han population. A total of 161 cases (72 men and 89 women; mean age, 43.8 ± 5.5 years) and 256 controls (119 men and 137 women; mean age, 42.1 ± 6.9 years) were included in the study. The observed frequencies of all tested genotypes in controls did not deviate from Hardy- Weinberg equilibrium (HWE). Compared with the II genotype, the DD frequency of ACE I/D polymorphism among cases was significantly different from controls (DD versus II: OR=2.94; 95% CI=1.61-5.42; p<0.05). In addition, compared with the I allele, the D allele among cases was significantly associated with psoriasis risk (D versus I: OR=1.61; 95% CI=1.21-2.21; p<0.05). In conclusion, the current study showed that ACE I/D polymorphism may influence the risk of psoriasis in a Chinese Han population.