Background Epidemiological studies on the association between asthma and cardiovascular disease have reported conflicting results. This cross‐sectional study evaluated the association between asthma and ischaemic heart disease (IHD)/stroke in Korean adults. Materials and methods Data from the Korean Genome and Epidemiology Study‐Health Examinees were used. Among 173 209 participants, 3162 asthmatic and 159 408 control participants were selected. Histories of asthma, IHD and stroke were obtained. Participants were categorized according to their current status of asthma management: 'well‐controlled', 'being treated', and 'not being treated'. Crude and adjusted (age, gender, body mass index, income, smoking, alcohol consumption, hypertension, diabetes, dyslipidaemia and nutritional intake) odds ratios (ORs) for IHD and stroke in asthmatic patients were analysed using a multiple logistic regression model. Results Participants with asthma reported a significantly higher prevalence of IHD (6.0% vs 3.0%) and stroke (2.3% vs 1.4%) than those without asthma (P < .001). Asthmatic participants had a higher OR (1.46, 95% confidence interval CI = 1.251‐1.71, P < .001) for IHD than those without asthma. The association between asthma and IHD was significant only in patients aged ≥53 years (men: adjusted OR = 1.31, 95% CI = 1.01‐1.70, P = .046; women: adjusted OR = 1.64, 95% CI = 1.32‐2.03, P < .001) according to age and sex and in the 'not being treated' asthma group (adjusted OR = 1.47, 95% CI = 1.14‐1.91, P = .003) according to the asthma management status. Stroke was not significantly associated with asthma (adjusted OR = 1.17, 95% CI = 0.92‐1.48, P = .203) in the adjusted model and all subgroup analyses. Conclusion Asthma was associated with IHD, mainly in older patients and untreated asthma patients, but not with stroke.