This paper investigates the effects of retirement on various health outcomes. Data stem from the first three waves of the English Longitudinal Study of Ageing (ELSA). With these informative data, non-parametric matching and instrumental variable (IV) methods are applied to identify causal effects. It is found that retirement significantly increases the risk of being diagnosed with a chronic condition. In particular, it raises the risk of a severe cardiovascular disease and cancer. This is also reflected in increased risk factors (e.g. BMI, cholesterol, blood pressure) and increased problems in physical activities. Furthermore, retirement worsens self-assessed health and an underlying health stock. Copyright © 2011 John Wiley & Sons, Ltd.