Background Coronary fistulae are communications between a coronary artery and a heart chamber or vessel. The final diagnosis is usually made by coronary angiography or computed tomographic (CT) angiography. Here we report a case by employing contrast echocardiography in diagnosis of a giant coronary aneurysm with right ventricle (RV) fistula. Case presentation The patient, a 29‐year‐old woman, referred to our institution with a complaint of palpitation occasionally. Transthoracic echocardiogram showed a spherical, echogenic structure in the apex of RV. Proximal to the aneurysm, the left anterior descending branch (LAD) remained enlarged (8–9 mm) and showed a fistulous communication with the echogenic structure. A contrast echocardiography was performed, and 4–5 cardiac cycle after the left ventricle was enhanced, the echogenic structure started to become more prominent and several fistulae were seen between RV and the echogenic structure. Computed tomography (CT) angiography and coronary angiography confirmed the dilation (9 mm in diameter) of the LAD with an aneurysm at the distal segment of the LAD, with a small amount of iodinated contrast agent flowing into the subsequent region of the RV, thereby characterizing a LAD‐to‐RV fistula. Conclusion The final diagnosis of fistula is usually made by coronary angiography or CT angiography. However, contrast echocardiography is also a well‐established method for the demonstration of intracardiac shunting. In this case, the contrast echocardiography clearly revealed one of the fistulae between the aneurysm and RV.