The electrocardiograms of 559 persons, 83% of the total population 85 years of age or over in the city of Tampere, were evaluated according to the classification of the modified Minnesota code. Electrocardiograms showed no codable item in only 3.6% of the subjects. The prevalence of the most frequent electrocardiographic findings was: T wave inversion 53.3%, counter-clockwise rotation 42.9%, ST junction depression 42.8%, premature beats 33.8%, Q-QS pattern 21.3% and atrial fibrillation 17.4%. The prevalence of left axis deviation, left anterior hemiblock and right bundle branch block was statistically significantly higher in men than in women. Electrocardiographic abnormalities suggestive of ischaemic heart disease were present in 45.3% with no statistically significant relation to sex or age. The results are discussed and compared with those of electrocardiographic studies concerning age groups over 80 and 90 years.