AbstractBackground  Recently, mutations in the filaggrin gene (FLG) have been shown to be a major predisposing factor for atopic dermatitis (AD).Objective  In this study, we evaluated the influence of four prevalent mutations (R501X, 2282del4, R2447X and S3247X) in a large cohort of 462 Austrian and German AD patients and in 402 control individuals.Results  We found a strong association of the FLG mutations with AD. Subgroup analysis revealed a significantly higher proportion of patients with an early age of disease onset and significantly higher median serum IgE levels among mutation carriers.Furthermore, we observed an overrepresentation of null alleles in AD patients with concomitant asthma compared with those without this co‐morbidity.Conclusion  Our data confirm and extend the knowledge of the influence of FLG mutations in AD.