Endometriosis, one of the most frequent diseases in gynecology, is a benign but invasive and metastatic disease. The altered expression of E-cadherin may play an important role in developing endometriosis. In this paper, we discuss the association of three single nucleotide polymorphisms (SNPs) on the E-cadherin gene and risk of endometriosis. We examined the genotype frequency of three polymorphisms in 152 endometriosis patients and 189 control women. There was a significant difference in the frequency of the E-cadherin 3'-UTR C --> T genotypes between endometriosis and controls (P = 0.01). The frequency of the C allele in patients (71.1%) was significantly higher than in the controls (63.8%; P = 0.04). When compared with the T/T + T/C genotypes, the C/C genotype had a significantly increased susceptibility to endometriosis, with an adjusted odds ratio of 1.79 (95% confidence interval = 1.17-2.76). No significant difference was found between endometriosis and control women on two polymorphisms (-160 C --> A, -347 G --> GA) at the gene promoter region of E-cadherin. The -160 C --> A and -347 G --> GA polymorphisms displayed linkage disequilibrium (D' = 0.999). The -160 A/-347 GA haplotype was only detected in endometriosis patients (2%). These data show a relation between the E-cadherin 3'-UTR C --> T polymorphism, the -160 A/-347 GA haplotype of two promoter polymorphisms and risk of endometriosis, suggesting a potential role in endometriosis development, at least in North Chinese women.