Background. Over the past three decades much has changed in the treatment and outcomes of patients suffering concurrently from both multiple myeloma (MM) and HIV. While the prevalence of MM appears to be higher in HIV-positive individuals than in those who are uninfected, early recognition of patients suffering from both diseases is difficult and little information is available on their demographics and clinical presentation. Objective. To compare the presenting features of HIV-positive patients diagnosed with MM with those of HIV-negative patients. Methods. A single-centre, retrospective cohort study included 16 HIV-positive and 73 HIV-negative patients diagnosed with MM, in order to compare variables related to the clinical presentation of both conditions. Results. HIV-positive patients presented with MM at a significantly younger age, and had fewer osteolytic lesions, less renal impairment and lower neutrophil counts. Disease stage, gender, pathological fractures, bone marrow plasmacytosis, plasmacytomas and lymphocyte counts were comparable, emphasising the difficulty of identifying these patients. The HIV-positive patients had relatively high CD4 counts and a low prevalence of abnormal Freelite kappa/lambda ratios. All HIV-positive patients presented with paraproteins of the immunoglobulin G (IgG) type, implying a possible relationship between MM and an IgG response to HIV antigens. Conclusions. On the basis of our findings and literature on the treatment of both diseases, we suggest that HIV be tested for routinely in younger MM patients, especially in areas with a high prevalence of HIV. The integration of our results into the sparse knowledge on the role of HIV infection-related MM provides possible new insights into the interaction between these diseases.