Records of 326 patients were analysed to determine the prevalence of coronary heart disease (CHD) in patients with valvular heart disease (VHD) and to identify the group in whom coronary arteriography is essential. Significant CHD (60% or more luminal narrowing) was found in 7 per cent of cases, and its prevalence was 3 per cent in mitral, 10 per cent in aortic, and 6 per cent in combined mitral and aortic valve disease. Angina was present in 14 per cent of patients with mitral, 39 per cent with aortic, and 21 per cent with combined mitral and aortic valve disease. Seventy-three per cent of patients with CHD had angina whereas only 19 per cent with angina had CHD. The prevalence of CHD was higher in patients above 50 years (13%) and in males (98%) as compared to those below 50 years (3%) and females (none). We conclude that the prevalence of CHD is low in our patients with VHD. Routine coronary arteriography is recommended only in males over the age of 50 years.