We compared transcranial Doppler (TCD) with transesophageal echocardiography (TEE) and transthoracic echocardiography (TTE) for the detection of right to left communication (RLC) in the heart. All patients explored from 2013 to 2016 in a vascular medicine unit to detect RLC by TCD were included. Right to left communication was detected by TCD monitoring for microembolic signals after intravenous injection of agitated 5% glucose and air. One hundred one patients were explored for RLC by TCD, 64 by TEE (not possible in 10, bubble injection in 51), and 93 by TTE because of unexplained stroke or arterial thrombosis (51 males, 50 females, age 51.0 ± 15.8 years) (bubble injection in 35). Fifty-three patients were positive after TCD (TEE: 4 negative, TTE: 7 negative). Of the negative patients after TCD, none was positive for TEE and 1 was positive for TTE with no evidence of patent foramen ovale. Transcranial Doppler was sensitive to detect RLC, even in patients with negative TTE or TTE. A negative TEE did not exclude RLC demonstrated by TCD. Transcranial Doppler might be proposed as first line to detect RLC.