The relationship between various non-invasive signs of hypertensive cardiac involvement and blood pressure (BP) was studied in 120 middle-aged men recruited from a BP-screening of a random population sample. The men, representing a wide range of BP, were divided into four BP groups (normotensive, and borderline, mild and moderate-severe hypertension), and were investigated by conventional electrocardiography (ECG), chest X-ray, echocardiography, apexcardiography/phonocardiography and corrected orthogonal ECG. In the hypertensive groups a lower proportion of subjects with signs of cardiac involvement were identified by conventional ECG and chest X-ray than by the other methods. A significant association between the prevalence of pathological findings and level of blood pressure (P < 0.05–0.01) was found for conventional and corrected orthogonal ECG and apexcardiography/phonocardiography. With echocardiography, concomitant increased thickness (> 12 mm) of both the interventricular septum and left ventricular posterior wall, but not of one structure alone, was significantly associated with BP (P < 0.05). In borderline subjects, pathological findings were surprisingly common. However, many of these subjects had single abnormalities, whereas those with higher BP had an increasing degree of multiple pathological findings. We conclude that in many hypertensives there are signs of cardiac involvement that can be revealed by means of sensitive non-invasive methods. Single signs can be revealed in mild hypertension but the number and severity of the different abnormalities increases (dramatically) with increasing BP. It is probable that these various types of cardiac involvement carry prognostic information that could help in treatment decisions.