Ventilation and cardiovascular function must be matched in all vertebrates to secure efficient delivery of oxygen to the respiring tissue as well as an adequate removal of waste products. The cardiorespiratory interaction is particularly evident in ectothermic vertebrates that typically exhibit a discontinuous breathing pattern with prolong apnoea where heart rate is very low and intermittent ventilatory bouts where heart rate may increase several-fold. The cardio-respiratory responses and their interactions are driven by central feed-forward mechanisms and afferent feed-back from peripheral receptors (1). The reflex roles of these receptors differ between fishes and air-breathing vertebrates. In fish, hypoxic stimulation of the branchial oxygen sensitive chemoreceptors that are homologues to the carotid chemoreceptors of mammals causes pronounced bradycardia and hyperventilation, while stimulation of O2 sensitive receptors and the resulting hyperventilation normally causes a tachycardia in air-breathing vertebrates (2,3). In amphibians and reptiles, the cardiorespiratory interactions also include selective changes in pulmonary perfusion achieved by changes in the cardiac shunt pattern (4). Taking an outset in the regulation of these responses, I will discuss a series of experiments attempting to reveal these functional correlates and potential selective value of the hypoxic bradycardia in fish and the cardiac shunt pattern (5,6). Finally, I will discuss how visceral organs appear to exert some cardiovascular control during digestion in reptiles, and possibly other vertebrates (7).