OBJECTIVE: The pathogenesis of vulvar vestibulitis syndrome remains unknown but may be related to a localized chronic inflammation. The relation between this syndrome and a polymorphism at position +3953 in the interleukin-1beta gene was examined. Allele 2 of this gene has been associated with increased pro-inflammatory immunity. STUDY DESIGN: Buccal or vestibular swabs from 59 women with strictly defined vulvar vestibulitis and from 48 healthy women were tested by polymerase chain reaction for the presence of two alleles at the +3953 interleukin-1beta locus. RESULTS: Allele 2 of the interleukin-1beta gene was identified in 27 (46%) women with vulvar vestibulitis as opposed to 12 (25%) control women (P=0.03). The interleukin-1beta 1,1 genotype was present in 36 (75%) controls as opposed to 32 (54%) vulvar vestibulitis syndrome patients (P=0.02). All subjects had been previously tested for induced interleukin-1beta production in response to bacterial lipopolysaccharide. In both patients and controls, possession of allele 2 was associated with a small but non-statistically significant increase in induced interleukin-1beta production. CONCLUSION: Allele 2 in the interleukin-1beta gene is more common in women with vulvar vestibulitis syndrome than in other women. Susceptibility to vulvar vestibulitis syndrome might be influenced by carriage of this polymorphism.