Purpose: Hydatid cysts in cardiac echinococcosis mostly involve left ventricle and septums. Up to this time, in these cases CT has been used complementary to echocardiography. Here, we report a right atrial hydatid cyst case with review of cardiac hydatid disease and the role of MR imaging in these cases. Method: On chest X-ray of a 57-year old man there were multiple parenchymal masses, and right cardiac contour was slightly prominent. Following chest x-ray, CT, echocardiography and MR imaging were performed. At cardiac surgery a large perforated cyst was extracted. Results: Both CT and MRI were effective in demonstrating the masses in pulmonary parenchyma, but due to cardiac motion, it was not possible to demonstrate the contents of the cyst in the right atrium by CT MR was as efficient as echocardiography in demonstrating the content of the mass in cardiac location. Conclusion: With MRI, it is possible to demonstrate the cyst in pulmonary and cardiac locations, and in cases like cardiac echinococcosis, MR imaging must be the choice of imaging modality complementary to echocardiography.