Considering that growing population of very young children is exposed to general anesthesia every year, it is of utmost importance to understand how and whether such practice may affect the development and growth of their very immature and vulnerable brains. Compelling evidence from animal studies suggests that an early exposure to general anesthesia is detrimental to normal brain development leading to structural and functional impairments of neurons and glia, and long-lasting impairments in normal emotional and cognitive development. Although the evidence from animal studies is overwhelming and confirmed across species examined from rodents to non-human primates, the evidence from human studies is inconsistent and not conclusive at present. In this review we focus on new developments in animal studies of anesthesia-induced developmental neurotoxicity and summarize recent clinical studies while focusing on outcome measures and exposure variables in terms of their utility for assessing cognitive and behavioral development in children.