HIV-associated lymphoma was first classified as an AIDS-defining disease by the American Center for Disease Control and Prevention (CDC) in 1985. Non-Hodgkin's lymphomas (NHLs) are frequent malignancies in AIDS patients. The risk of NHL in the case of an underlying HIV infection is estimated to be 100 times greater than in the general population, and it increases with the progression of the retrovirus-related immunosuppression. Cases of HIV-related non-Hodgkin's lymphoma are widely documented in the literature. In this article we present three cases of NHL and HIV hospitalized over a period of three years (2013-2016) at our specialized department for AIDS patients. Two of them were initially diagnosed with NHL and then with HIV infection. In one patient, NHL developed despite the patient's taking background antiretroviral therapy. The first case was a 38-year-old male diagnosed previously with HIV, who developed a palpable mass in the left zygomatic bone. The second case was a 52-year-old male who was first diagnosed with a cutaneous lymphoma, and subsequently with HIV infection. The third patient was a 63-year-old male who presented with two palpable masses: one in the left part of the mandible, and the other in the right inguinal region, the latter subsequently diagnosed as lymphoma. Following the latter diagnosis, the patient tested positive for HIV. The histological findings of the three lymphomas were as follows: an NHL plasmoblastic lymphoma, a cutaneous large B-cell anaplastic lymphoma, and a diffuse large B-cell lymphoma. The first patient received antiretroviral therapy (ART) and EPOCH (etoposide, pharmarubicin, vincristin, endoxane, uromitexan) plus radiotherapy, while the second received ART and CHOEP (endoxan, epirubicin, vincristin, etoposide, prednisolone). The third patient died a few days after beginning antiretroviral therapy.