We report a case of a 41-year-old male with human immunodeficiency virus (HIV)-associated lymphoproliferative disease (LPD) who was successfully treated with highly active antiretroviral therapy (HAART). He presented with epigastralgia, and an upper endoscopic examination revealed submucosal tumors and ulcerations in his stomach. Histopathologic examination of a biopsy specimen resulted in a diagnosis of diffuse large B-cell lymphoma. He also showed systemic lymphadenopathy; whereas, a concurrent inguinal lymph node biopsy produced a diagnosis of follicular hyperplasia. He was treated with CHOP chemotherapy but the response was poor. He demonstrated several immunological abnormalities, such as eosinophilia and bone marrow insufficiency, and was suspected to be in an immunocompromised state. He was examined for HIV infection and turned out to be positive. The gastric and inguinal lymph node specimens were re-evaluated and diagnoses of HIV-LPD and HIV lymphadenitis were made, respectively. He was treated with HAART and achieved complete remission and has remained tumor-free for 20 months. To the best of our knowledge, there is no previous report in which HIV-LPD was successfully treated with antiretroviral therapy alone. It is assumed that HAART resulted in the restoration of anti-tumor immunity in this case, which led to the eradication of LPD cells.