Several studies indicate genetic involvement of Th2 cytokines in allergic diseases. Interleukin (IL)‐13 has been mapped to the cytokine cluster on chromosome 5q31–33, which has been associated with atopic conditions. Recently, an association was reported between the T allele in a promoter polymorphism in the IL‐13 gene (C to T exchange) at position −1055 and allergic asthma in a population study in the Netherlands. This observation was apparently confirmed in a case–control study using probands and spouses from a Dutch asthma family study, but the polymorphism in that study was reported to occur at position −1111. In the present study, we established that this polymorphism is located at position −1024 relative to the ATG translation initiation codon, and investigated whether it confers a genetic predisposition to atopic conditions and the Th1 condition multiple sclerosis (MS) in Caucasian subjects. We confirmed the association between the IL‐13 −1024TT genoype and inhalation allergy (P = 2.4E‐02). By combining the data from the three studies, we demonstrated a strong association (P = 1.09E‐05) between the IL‐13 −1024 marker and inhalation allergy. Furthermore, we showed for the first time that this association also exists in atopic dermatitis (P = 2.0E‐02). No association with MS was found.