Background: Hashimoto’s thyroiditis (HT) is a T-cell-mediated autoimmune disease. Cytokinesplay a crucial role in modulating immune responses that affect the balance betweenmaintenance of self-tolerance and initiation of autoimmunity. Thus, we aimed toexplore the possible associations of interleukin (IL-1β) −511C/T (rs16944) and IL-1β+3954C/T (rs1143634) gene polymorphisms with susceptibility of HT, and to clarifythe impact of these polymorphisms on thyroid function of Egyptian women. Patients and methods: Polymorphisms of the IL-1β −511 and IL-1β +3954 genes were assessed in acase–control study comprising 110 HT patients and 90 controls. Genetic variantswere genotyped by multiplex PCR. Polymorphisms of the IL-1β were studied byPCR-restriction fragment length polymorphism analysis. Results: Our results revealed that the IL-1β −511 CT genotype distribution was significantlyhigher in HT patients than in controls. With regard to IL-1β +3954 genepolymorphisms, our results showed that there was a nonsignificant differencebetween the control and HT groups. Women carrying TT and CT genotype ofIL-1β −511 had significantly higher values of C-reactive protein, thyroid-stimulatinghormone, anti-thyroid peroxidase, and anti-thyroglobulin. As regards the IL-1βserum level, women carrying TT and TC genotype of IL-1β −511 hadsignificantly higher values compared with patients carrying the CC genotype.Moreover, anti-thyroglobulin and free thyroxine were the only independentlycorrelated factors with IL-1β serum level by linear regression analysis. Conclusion: CT genotype distribution was significantly higher in patients with HT than in controlswith regard to IL-1β −511 (C>T) gene polymorphisms.