We study the importance of childhood socioeconomic conditions in explaining differences in life expectancy using data from a sample of around 5,000 children collected in the UK in 1937-39, who have been traced through official death records up to 2005. We estimate a number of duration of life models that control for unobserved household heterogeneity. Our results confirm that childhood conditions such as household income and the quality of the home environment are significant predictors of longevity. Importantly, however, the role of socio-economic status appears to differ across cause of death, with household income only being a significant predictor of death from cancer. Moreover, we find that children born in a location with relatively high infant mortality rates live significantly fewer years, that 1st born children in the family live significantly more years, and that there is a very high correlation in longevity across children from the same family across all causes of death. We estimate that the difference in life expectancy between ‘good’ and ‘bad’ households is as large as 11 years.