The course of disease in 119 HIV-infected patients (117 men, 2 women; median age 38.5 years) with malignant tumours other than Kaposi's sarcoma was analyzed in a multi-centre retrospective study. This was conducted to obtain initial information concerning the incidence, clinical features and results of therapy in HIV-associated neoplasms, especially malignant lymphomas. The most frequent tumour was malignant non-Hodgkin's lymphoma (98 patients, 82.5%), seven patients had Hodgkin's disease, five had solid tumours, four a polyclonal lymphoproliferative syndrome, three an acute lymphocytic leukaemia, and two had other lymphoproliferative diseases. 58% of the non-Hodgkin's lymphomas occurred in patients with marked immunodeficiency, 85% were high grade malignancies and 47% had primary extranodal disease. 56% of primary nodal lymphomas also had visceral spread (Stage IV). Lymphoblastic non-Hodgkin's lymphoma was more common in patients with favourable immunological status, presented less frequently with primary extranodal disease, was diagnosed earlier than other non-Hodgkin's lymphomas, and appeared to carry a better prognosis. 78 out of the 98 patients with non-Hodgkin's lymphoma had been treated, 66 with cytotoxics. The median survival time was 6 months. Longer remission periods, of at least 12 months, were seen in ten of the 78 patients (13%). Despite the overall poor prognosis and the pre-existing immune defect, palliative (chemo-)therapeutic measures are both justified and promising, and may also result in life-prolonging remissions.