To investigate the frequency of cardiac valve regurgitation related with low dose dopamine agonists in patients with Parkinson's disease (PD), echocardiograms were analyzed in 527 consecutive PD patients (448 patients treated with dopamine agonists, 79 patients never treated with dopamine agonists as age-matched controls). The frequency of mild or above mild regurgitation of the aortic valve (AR) was significantly higher in the cabergoline group (13.7%, P < 0.05) compared with the controls (2.5%). Odds ratio adjusted by age and sex for AR was significantly higher in the cabergoline group (OR, 6.45; 95% CI, 1.46-28.60; P = 0.01): odds ratio was significantly higher in patients treated with higher daily doses (OR, 14.41; 95% CI, 3.08-67.38; P = 0.0007) and higher cumulative doses (OR, 15.29; 95% CI, 3.19-73.18; P = 0.0006). No statistical difference was identified in the frequency of the tricuspid and mitral regurgitation. None of the other dopamine agonist groups including pergolide gave higher frequency or higher odds ratio compared with the controls. None of our patients showed severe regurgitation or was operated for valvular heart disease. The question as to whether or not longer duration of low dose dopamine agonist treatment would yield the same results needs further studies.