Prematurely born neonates are often admitted to the neonatal intensive care unit (NICU), where they will experience adverse life events like stress, pain, and exposure to analgesics. This kind of events in early life influences the postnatal maturation of the nociceptive system, and can therefore alter future responses to painful events. However, the neurobiological mechanisms leading to these lifelong effects are still unclear. In this symposium, we address new findings on how early life exposure to adversities like stress, pain, and analgesics is received by the developing nociceptive system and can influence its maturation. First, we will describe optimized methods to quantify personalized profiles of adversity experiences in the NICU, and explore pain processing changes that occur during the weeks that preterm or ill newborns spend hospitalized. By incorporating preclinical models, this symposium will examine how early life adversities can influence key stages of nociceptive development in the postnatal phase. Finally, we will assess how exposure to analgesics during early development can shape nociception and analgesic efficacy throughout the lifespan.