A life-course approach to chronic-disease epidemiology uses a multidisciplinary framework to understand the importance of time and timing in associations between exposures and outcomes at the individual and population levels. Such an approach to chronic diseases is enriched by specification of the particular manner in which timing in relation to physical growth, reproduction, infection, social mobility, behavioural transitions etc. can influence various adult chronic diseases in different ways, and more ambitiously by how these temporal processes are interconnected and manifested in health inequalities within a population and in population-level disease trends. The paper will discuss some historical background to life-course epidemiology and theoretical models of life-course processes, and will review some of the empirical evidence linking life-course processes to CHD, haemorrhagic stroke, stomach cancer and other chronic diseases in adulthood. It will also underscore that a life-course approach offers a way to conceptualize how underlying socio-environmental determinants of health, experienced at different life-course stages, can differentially influence the development of chronic diseases, as mediated through proximal specific biological processes.