Blau syndrome is a chronic granulomatous disease with an autosomal dominant trait characterized by the triad granulomatous dermatitis, arthritis, and uveitis. It is caused by mutations in the NOD2 gene, also termed the CARD15 gene.To report a novel mutation in the NOD2 gene associated with Blau syndrome.The proband was a 68-year-old ethnic Norwegian male who had uveitis and arthritis since 10 years of age followed by lifelong recurrent arthritis and chronic eye involvement. Genetic analysis showed a heterozygous c.1814 C>A, T605N mutation in NOD2 that has not previously been described. All of his three children had Blau syndrome and had inherited the NOD2 mutation. The proband's first son had exanthema, arthritis, and uveitis from 10 years of age and later presented with granulomatous lymphadenopathy, granulomatous parotitis, and granulomatous intestinal inflammation. The proband's daughter had arthritis, uveitis, and exanthema from 3 years of age. The proband's second son had uveitis, exanthema, and arthritis from 1.5 years of age. None of the cases had any involvement of the heart or lungs.We report a novel Blau syndrome-associated mutation with an autosomal dominant heritage. Most likely the mutation has arisen de novo in the proband. Genetic counselling and antenatal diagnostics should be available to the involved families.