We performed transesophageal echocardiography (TEE) and transcranial-color flow imaging (TC-CFI) in 38 patients (25 men, 13 women, mean age 51.5 years old) with cerebrovascular or cardiac disease in order to evaluate an accuracy in diagnosing right-to-left shunts (RLS) in the heart by TC-CFI as compared to TEE findings. We rapidly injected a mixture of 9 ml of cold saline and 1.0 ml of air into the antecubital vein during Valsalva maneuver. In TEE study, we took RLS positive when interatrial shunting of contrast microcavitations into the left atrium was visualized after complete opacification of the right atrium. In TC-CFI study, we considered RLS positive when we detected the high intensity transient signals (HITS) on the middle cerebral artery. The both studies were positive in 15 patients and negative in 19. Two patients were positive in TC-CFI and negative in TEE while the other two patients were negative in TC-CFI and positive in TEE. Therefore, the sensitivity of TC-CFI in diagnosing RLS was 88%, the specificity 90%, and the accuracy 89%. It seems that TC-CFI is a useful tool to estimate the RLS.