Cognitive decline amongst older people is associated with poor health and lower quality of life. Previous studies demonstrate that retirement is a particularly critical period for cognitive decline and highlight the importance of post-retirement behaviours. Using longitudinal data from the Survey of Health, Ageing and Retirement in Europe, this study examines the effect of information technology usage on cognitive function, focusing specifically on internet usage. To address the endogenous relationship between cognitive function and IT usage, we adopt an instrumental variable approach that exploits variation in pre-retirement computer exposure due to the uneven computerisation of occupations across countries during the 1980s and 1990s. Our results suggest moderating effects of IT usage on the cognitive decline of retirees. These results are concentrated amongst people who worked in middle-skill occupations, occupations that have previously been shown to have experienced large-scale computerisation.