Piglet death during the perinatal and lactation period is one of the more easily identified causes of reduced production efficiency in swine herds. Pre-weaning mortality rates vary between 12 and 25%. The present review analyses factors related with non-infectious pre-weaning mortality. Among the maternal factors, farrowing and intra-uterine asphyxia, behaviour and maternal ability are discussed. Piglet factors include newborn vigour, teat seeking ability, acidosis, hypothermia and hypoglucemia. Even though there had been technological changes and improvements in husbandry, housing designs and preventive measures, piglet mortality in lactation remains a major economical and welfare problem. The major causes of pre-weaning mortality are those associated with basic husbandry skills, starvation and crushing by the sow. One potential alternative to reduce neonatal mortality in pigs is the monitoring of foetal stress during birth, it is also important to consider the physiological, behavioural and biochemical changes that take place during early lactation which subsequently affect the vitality, maturity and development of neonatal pigs. A mortality rate of say 8% of piglets born alive is possible and should be the target, getting more knowledge of factors influencing piglet non-infectious mortality within the first three days may help improve piglet welfare.