After the introduction of highly active antiretroviral therapy (HAART), there has been a decrease in the incidence of lymphoma among the HIV-infected population and also significantly improved survival rates. We describe a remarkable case of an HIV-infected patient with advanced stage IV diffuse large B-cell lymphoma (DLBCL), completely regressed with the use of HAART alone. He remained disease-free for 6 years and he achieved cure without chemotherapy. Although several cases of low-grade lymphoma with complete regression were reported, we could not find any case of stage IV high-grade malignant lymphoma with HAART alone in complete remission for over 5 years from our review of the literature. This unique case shows the importance of HAART in improving survival and achieving cure in HIV–high-grade malignant lymphoma.