Objective To study the expressions of IL-1 receptor type-Ⅰ(ΒIL-1RI) mRNA and IL-1β protein in the rat carotid body. Methods In situ hybridization, immunofluorescence double staining and Western blotting methods were used. Results The result of in situ  hybridization showed that the positive signal of IL-1β mRNA was mainly located in the glomus cells of the carotid body. The result of immunofluorescence double staining showed that IL-1β protein also expressed in the glomus cells of the organ. The Western blotting proved that the IL-1β immunoreactive band appeared at 18?kD, consi