Cardiac involvement by non-Hodgkin's lymphoma is not uncommon, however rarely diagnosed during life due to nonspecific clinical presentation. We report a case of secondary cardiac lymphoma in patient who presented with new-onset atrial fibrillation. Cardiac lymphoma was in a form of bulky right atrial mass, infiltrating the atrial septum and cavo-atrial junction with concomitant mild pericardial effusion. In the present case, we illustrate complementary role of transthoracic, transesophageal echocardiography and multislice CT scan with three-dimensional reconstruction, in detection and evaluation of secondary cardiac tumor. Usefulness of echocardiography to follow up the effects of chemotherapy is also shown.