Veterinary knowledge of rodent respiratory disease was initially based on laboratory animal medicine. As these pets have increased in popularity, and owners are more inclined to present them to the veterinary surgeon, diagnostic techniques and treatment options have improved. Respiratory disease is one of the most common problems encountered in pet mice and rats, mainly caused by Mycoplasma pulmonis. In guinea pigs Bordetella bronchiseptica is the most common respiratory pathogen. Respiratory disease is less common in hamsters and chinchillas and rare in gerbils and degus. Animal husbandry, environmental conditions and immune status all play a part in pathogenesis. This chapter examines the General approach to respiratory cases; Common respiratory diseases; and Cardiovascular disease.