Retinitis pigmentosa defines a genetically heterogenous group of disorders characterized by degenerations of photoreceptors and pigment epithelium. This article reviews our current knowledge of the genetical, clinical and pathophysiological aspects of this disease complex. Therapeutic concepts under current investigation are discussed as well. In recent years tremendous new insights have been made using molecular techniques for the investigation of retinal dystrophies. Ophthalmoscopically very similar patterns of photoreceptor dystrophies have been related to different gene mutations. In contrast, mutations in a single gene may cause different clinical patterns of photoreceptor dystrophies. Therefore, these recent results suggest that a reclassification of retinal dystrophies on the basis of their genetic origin may be favourable. In the future molecular genetics and the recent developments may play an increasing role for clinical classification and evaluation of photoreceptor dystrophies. The continued clinical and experimental research on hereditary disorders may help to elucidate further the wide disease spectrum and thereby developing new classifications and efficient therapeutic concepts.