The research presented in this thesis comprises a body of work dedicated to continuing and enriching past exploration into the impact cumulative life stress exerts on ageing cognition. In order to extend previous work into this topic, behavioural measures were paired with electroencephalographic recordings of the cortical oscillatory activity thought to underlie cognitive operations. In a theoretical sense, work presented in this thesis strengthens past investigations highlighting the adverse effects of life stress on elderly peoples’ working memory abilities by replicating the effect under conditions of increased experimental rigour. It further provides evidence that the detrimental effects of cumulative stress extend to the domains of executive control and spatial memory. Electrophysiological findings obtained during task execution and at rest indicate pronounced changes in the oscillatory activity of aged high stress individuals’ delta, theta, alpha and gamma bands and are thus the first to demonstrate that cumulative stress affects the underlying neural processes related to successful task execution. As such, from a methodological standpoint, the current research strongly advocates the use of neuroscientific tools such as the electroencephalogram to gain an increased understanding of the mechanisms by which increased stress exposure evokes progressive cognitive decline in old age. Combined, the work presented in this thesis demonstrates the negative consequences of leading a highly stressful life for the integrity of multiple cognitive functions in old age and is the first to provide an indication of how cumulative stress affects both cortical and (indirectly) subcortical regions of the brain necessary for successful cognitive functioning.