Attention to the unique physiology and particular requirements of individuals within neonatal/pediatric age group will improve our ability to provide safe, effective anesthesia and analgesia. A thorough physical examination, including careful auscultation of the heart, is an essential component of preanesthetic assessment. The physiology of neonates results in differences in pharmacokinetics and pharmacodynamics that contribute to altered response to drugs. Hydration status and fluid requirements should be evaluated. As with patients of any age, anesthetic drugs should be titrated 'to effect' and patients closely monitored. Inhaled anesthetic drugs are minimally metabolized and primarily eliminated by the lungs, and are thus ideal for maintenance of anesthesia in animals with immature hepatic or renal function. Along with a carefully chosen anesthetic protocol and appropriate drug dosing, physiologic support and vigilant monitoring are important during anesthesia to minimize patient risk.