Respiratory distress is a common presentation in veterinary medicine, and prompt, effective management is paramount. Treating these animals can be challenging, as many are too distressed to be handled extensively. Excessive manipulation can result in exacerbation of respiratory distress, haemoglobin desaturation and respiratory arrest. Thus, in unstable animals, it is very important to limit diagnostic testing. Instead, initial efforts should be focused on stabilization and application of non-specific respiratory support modalities, such as oxygen supplementation. The history and signalment, observation of the pattern of respiration, and a brief physical examination are all used to make a clinical estimate of the anatomical location of disease within the respiratory tract, thereby directing effective emergency therapy to stabilize the patient prior to diagnostic testing. Depending on the cause of respiratory distress, a variety of emergency interventions may be necessary, including drug therapy, tracheostomy, thoracocentesis or thoracostomy tube placement, and positive pressure ventilation. This chapter looks at Physiology; History; Initial observation; Physical examination; Initial stabilization; Initial management based on disease location; and Initial diagnostic tests.