Primary testicular lymphoma (PTL) is a rare testicular tumor representing less than 9% of all testicular cancers. PTL usually tends to spread to or relapse at nodal structures or extra-nodal sites such as contralateral testes, central nervous system, skin, lung, pleura, waldeyer's ring and soft tissues. We present a case of PTL with huge left atrial mass, an extremely unusual site of involvement. Early disease usually carries a good prognosis, whereas advanced stage carries an extremely poor prognosis. Herein, we report the complete remission to date in a patient with advanced stage PTL with huge left atrial mass, treated with systemic rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone and intrathecal methotrexate. A brief review of literature focusing on various aspects of management of primary testicular lymphoma and lymphomatous involvement of heart is also discussed.