Objective: To investigate the role of selenoprotein W1 (SEPW1) single nucleotide polymorphism (SNP) in etiopathogenesis of pre-eclampsia (PE) and its association with maternal selenoprotein W (SelW) and selenium levels. Materials and methods: In this study, 98 pregnant women who were diagnosed with PE and 100 healthy pregnant controls were investigated. To identify the polymorphism of the SEPW1 gene (rs3786777), allele-specific polymerase chain reaction (ASPCR) analysis was used. Serum selenium levels and plasma SelW levels were measured by graphite-furnace atomic absorption spectrophotometry and by ELISA, respectively. Results: Maternal selenium levels (mu g/L) were 92.56 +/- 6.10 and 86.26 +/- 6.33 in pregnant women with and without PE, respectively (p > 0.05). On the other hand, SelW levels (ng/mL) were significantly lower in PE (72.08 +/- 8.10) compared to controls (89.29 +/- 6.99) (p < 0.01). The frequencies of the CC, CA, and AA genotypes were found to be 26%, 61%, and 13% in pregnant women with PE and 28%, 55%, and 17% in healthy pregnant controls. The distribution of the SEPW1 genotypes and alleles did not differ significantly among subjects with and without PE. In PE patients, SelW levels were lower in CC and CA genotypes compared to controls (p < 0.05 and p < 0.001). Conclusion: SEPW1 gene polymorphism did not seem to affect risk of PE in our population. However, SelW levels were low in some genotypes of the gene, suggesting that SelW might have played a role in the etiopathogenesis of PE.