Nowadays the cardiovascular diseases particularly ischaemic heart disease (IHD) are the most frequent causes of death in Poland. Some of patients with IHD are completely asymptomatic. These subjects are more susceptible to sudden coronary events due to lack of diagnosis and treatment. Cohn divided patients with asymptomatic ischaemia (AI) into three groups: completely asymptomatic, asymptomatic patients after myocardial infarction, patients with painful angina who have some ischaemic events asymptomatic. Some causes of AI are: increased pain threshold, increased beta-endorphin levels, impairment of pain pathways, smaller ischaemic regions in comparison with painful angina, psychological factors, transient platelet microaggregates. Estimated prevalence of AI is about 2-4% of total population and is larger in the group of patients with multiple coronary disease risk factors especially with diabetes mellitus (autonomic neuropathy). In the patients after myocardial infarction the prevalence of AI is between 30-70% and it is associated with poorer prognosis. In subjects with painful angina 70-80% of total ischaemic episodes detected by 24-hour ECG monitoring is asymptomatic. The most useful methods for diagnosis of AI are ECG exercise test and ambulatory 24-hour ECG monitoring, although they may sometimes produce false positive results. Other tests are not widely performed and their use is restricted to specific circumstances. Some cases are finally solved by coronary angiography. Although screening in whole population is not cost-effective, but in some groups is necessary (people with many risk factors of IHD, people of certain professions--plane pilots, etc.). Treatment of AI does not vary from treatment of symptomatic IHD. Basic drugs used are: aspirin, beta-blockers, calcium channel blockers, long time acting nitrates. Positive effect of statins is also observed. The most beneficial is invasive treatment--CABG is more efficient than PTCA. Moreover the treatment of symptomatic IHD should be oriented not only to eliminate the symptoms but also to withdraw episodes of silent ischaemia confirmed by 24-h ECG monitoring or ECG exercise test.