SummaryBackgroundAtopy is the familial or personal propensity to develop immunoglobulin E (IgE) antibodies against common environmental allergens and is associated with high risk of allergic disease. It has been proposed that atopy may have effects on risk of cardiovascular disease and cancer.ObjectivesWe investigated the association of atopy with all‐cause and cause‐specific mortality.MethodsWe included a total of 14 849 individuals from five Danish population‐based cohorts with measurements of atopy defined as serum‐specific IgE positivity against inhalant allergens. Participants were followed by linkage to the Danish Registry of Causes of Death to obtain information on mortality status and cause of death (median follow‐up time 11.3 years). The relative mortality risk was estimated by Cox regression and expressed as hazard ratios, HRs (95% confidence intervals, CIs).ResultsA total of 1776 person died during follow‐up. The mortality risk for atopics vs. non‐atopics was: for all‐cause mortality (HR = 1.03, 95% CI: 0.90, 1.17); neoplasms (HR = 0.86, 95% CI: 0.69, 1.06); endocrine, nutritional and metabolic disorders (HR = 1.48, 95% CI: 0.71, 3.08); mental and behavioural disorders (HR = 2.26, 95% CI: 1.18, 4.30); diseases of the nervous system (HR = 1.36, 95% CI: 0.65, 2.87); diseases of the circulatory system (HR = 1.00, 95% CI: 0.78, 1.29); diseases of the respiratory system (HR = 0.94, 95% CI: 0.55, 1.60); and diseases of the digestive system (HR = 1.75, 95% CI: 1.03, 2.98).Conclusions & Clinical RelevanceWe found no statistically significant association between atopy and all‐cause mortality. However, atopy was associated with a significantly higher risk of dying from mental and behavioural disorders and gastrointestinal diseases, particularly liver diseases, and a lower risk of dying from breast cancer, but these associations were not statistically significant when applying the Bonferroni adjusted significance level. Further studies are needed to confirm our findings.