Forty patients, 30 men and 10 women with an average age of 38.47 +/- 11.07 years, suffering from ankylosing spondylitis and attending a Rheumatology Outpatient Clinic, were evaluated for cardiovascular involvement. The evaluation was based on patients' clinical observation, electrocardiography, echocardiography, and chest x-ray. More than a simple review, this study was undertaken with the aim of arriving at a better clinical definition of the cardiovascular manifestations found in ankylosing spondylitis. In fact, of the 40 patients, 8 (20%) had systemic hypertension for which an explanation could not be found, 4 of whom were less than forty-five years old; the echocardiogram showed mitral valve prolapse in 4 patients (10%), 2 of them with a systolic murmur and other 2 with a protosystolic click on auscultation. More significant than the changes in conduction was the finding of a sinus bradycardia in 9 patients (22.5%), and a PR interval below 120 msec in 3 patients (7.5%). The authors conclude that the extension of cardiovascular changes in ankylosing spondylitis is more vast than usually acknowledged.