Background The ageing of the population raises the need to study forgoing treatment decisions among older people. Aim To describe the incidence and decision-making of forgoing treatment and identify age-related differences. Methods A nationwide study of a stratified sample from the Statistics Netherlands death registry to which all deaths were reported in 2010. All attending physicians of those deaths received a questionnaire about end-of-life decisions. 6600 cases were studied. We examined three age groups: 17–64, 65–79, and 80 and above. Logistic regression analyses were performed to identify age-related differences controlling for other patient characteristics. Results Forgoing treatment occurred in 37% of the total population, with a significant increase in the incidence across age. The most common treatments withheld/withdrawn were artificial hydration/nutrition, medication and antibiotics. Age-related differences were found, especially for withholding artificial hydration/nutrition among patients aged 65–79 (OR 2.04), and for withdrawing medication (OR 2.51) and antibiotics (OR 2.10) among the oldest when compared to the youngest patients. The most common reason for making the decision was ‘no chance of improvement’. The likelihood of forgoing treatment due to ‘loss of dignity’ was higher for the oldest (OR 2.32), as well as due to the request/wish of the patient (OR 1.97), when compared to the youngest patients. Conclusions Forgoing treatment occurred in a substantial proportion of older people, and more often than in younger age groups. The avoidance of burdensome treatment solely to prolong life suggests a better acceptance that these patients are nearing death.