We distinguish between part-time and full-time work activity and analyse their effects on the physical and mental health conditions of older workers in Europe. We use statutory eligibility ages for receiving retirement benefits as instruments for part-time and full-time work decisions to avoid the potential bias that deteriorating health conditions can cause employees to work fewer hours or not at all. We also control for unobserved heterogeneity across individuals. We find that working full-time deteriorates general health, reduces body weight, increases depression symptoms, and has a negative effect on word recall but a positive effect on numeracy skills. Working part-time has the opposite effects that are larger in magnitude. A comparison of the results obtained in Europe with those obtained in the United States in an earlier study shows that health responses to working part-time and full-time in old age differ across Europe and the United States.