ABSTRACTThe main pet rodent species are introduced with some brief notes on their suitability as pets and normal behaviour. The general clinical features of disease are discussed with some emphasis on species variation. The important diseases that occur in the United Kingdom are described under the headings of respiratory disease, diseases of the alimentary tract, diseases of the central nervous system, skin lesions, musculoskeletal disorders, palpable swellings, urinogenital disorders, diseases of pregnancy and injuries.