SummaryWe report on a homosexual male with the acquired immune deficiency syndrome and nonHodgkin’s lymphoma, who is to our knowledge the first case of its kind, described in Belgium.As previously reported, these lymphomas are mostly high grade malignant, with a B-cell or unknown immunologic phenotype and have a poor prognosis. Extranodal involvement, particularly of the central nervous system and of the bone marrow, is frequent.The potential transforming properties of Herpes group virus such as Epstein-Barr virus, as well as the defective immunoregulation of the Bcells population activated by multiple antigenic stimuli are considered as possible pathogenic mechanisms.