An overview of immunohistological and molecular genetic methods for diagnosis of Alport syndrome (AS) is given with practical experience from groups of authors' observations. Immunofluorescent investigation using antibodies against alfa chains of collagen IV was performed on cryostat sections from 29 punction nephrobiopsies and 9 skin excisions taken for support of differential diagnosis of AS particularly against the thin membranes glomerulopathy. Alfa chains deviations in other renal diseases were followed in another 14 cases. Molecular genetical investigation of AS by an indirect DNA diagnostics was performed in 35 families with presumed AS and in 27 patients with probable mutation a mutation screening of COL4AS gene by a direct method SSCP was made. The mutation was proved in 10 cases. Because of genotypical and phenotypical variability of AS the diagnostic gain only increases when all the accessible methods are combined.