The diagnosis of hereditary retinal dystrophies has been improved by various possibilities in recent years. On one hand, new clinical examination methods have been developed (e.g. multifocal ERG, autofluorescence). On the other hand, the marked progression of molecular genetic knowledge has led to the determination of several new genes in recent months. To date 121 gene locations and 56 cloned genes associated with hereditary retinal dystrophies are known. The impact of the new clinical methods for diagnosis and differential diagnosis as well as the indications for these techniques will be outlined. In addition, the molecular genetic knowledge and the indications for molecular genetic testing will be discussed.