Chlamydia pneumoniae has been associated with atherosclerosis, although no causal association has been established. Employing culture and polymerase chain reaction in aortic valves with calcific and degenerative arteriosclerotic changes from 23 non-consecutive patients undergoing aortic valve replacement, C. pneumoniae was not detected in any of the valves. 19/22 patients had serological evidence of past infection with C. pneumoniae. Our findings do not provide supportive evidence for the hypothesis that C. pneumoniae is associated with calcific or degenerative arteriosclerotic aortic heart valve disease.