Background: Recurrent aphthous stomatitis (RAS) is a multifactorial disease with unclear etiopathogenesis in which disturbance of immunological processes may be involved. The aim of our study was to investigate three single nucleotide polymor- phisms (SNPs) rs3806265, rs4612666, rs10754558 in NOD-like receptor 3 (NLRP3 ), the gene encoding the component of inflammasome, in patients with RAS and healthy controls in the Czech population. Methods: A total of 207 subjects were included in this case-control study. Sixty- four patients with RAS and 143 healthy controls were genotyped by a method based on polymerase chain reaction using 5 0 nuclease TaqMan â assays. Detailed anamnestic, clinical, and laboratory data were obtained from all subjects. Results: The allele and genotype frequencies of NLRP3 polymorphisms (rs10754558 and rs3806265) between both groups were similar. However, statistically significant differences in NLRP3 rs4612666 genotypes between the patients with RAS and controls were found; carriers of the TT genotype had a higher risk of developing RAS than subjects with the CT+CC genotypes (OR = 14.69, 95%CI = 1.73-124.72, P = .004, P corr < .05). No associations between NLRP3 haplotypes and RAS were observed. Conclusions: Our study indicates that the NLRP3 rs4612666 polymorphism may be involved in the development of RAS in the Czech population.