In coronary artery disease (CAD), a potentially reversible factor leading to cardiac death is left ventricular hypertrophy (LVH). While the electrocardiogram (ECG) is a widely available way to diagnose LVH, its sensitivity and specificity has never been assessed in this particular patient group where added ischaemic changes on ECG might complicate things. Furthermore, there are at least 11 different ECG criteria proposed to identify LVH. We sought to determine how many cases of echocardiography (echo) LVH would be missed if all of these different ECG criteria were applied in a group of stable, treated angina patients. A total of 241 consecutive patients with angiographically confirmed CAD were prospectively recruited and 11 ECG criteria were assessed on each subject and compared with the presence or absence of LVH on echo. Individual sensitivity, specificity, positive predictive value and negative predictive value were calculated for each ECG LVH criteria. The prevalence of echo LVH in the entire CAD population was 43%. All the proposed ECG criteria were poor at identifying echo LVH. The Cornell product yielded the highest rate of change value but still missed up to 80% of the echo LVH cases. We conclude that in a group of stable, treated angina patients, ECG is an unreliable method of identifying LVH. As LVH is very common in this patient population, screening by means of echo might be indicated. This will enable intensified efforts to ensure LVH regression, which is associated with reduction in both cardiovascular morbidity and mortality.