Population ageing is expected to lead to a rise of chronic conditions and multimorbidity. The life course perspective can give insights into different pathways and the role trajectories and life events play in health in later life. Moreover, socioeconomic conditions have been identified as a key factor by which health varies. Therefore, the main aim was to study the life course construction of health inequalities in old age. This thesis contains three papers using data from the Survey of Health, Ageing, and Retirement in Europe. Article 1 describes the importance of doing life course research in the general population by looking at the effect of childhood socioeconomic conditions on cancer in later life. Article 2 studies associations of life course socioeconomic conditions with frailty. Article 3 further explores different possible pathways in the life course that influence frailty, including adverse life events, with a focus on variation across welfare regimes.