Out of 323 patients with Hodgkin's disease CS I or II treated during the period 1969 to 1983 at Denmark's Finsen Institute, 35 presented with infradiaphragmatic disease. Patients with infradiaphragmatic presentation were older than patients with supradiaphragmatic presentation and were more often in stage II as opposed to stage I. NS histology was less prevalent among infradiaphragmatic than among supradiaphragmatic patients. Disease-free survival and overall survival was poorer in infradiaphragmatic patients. When other factors of prognostic importance were taken into account in a multivariate analysis, infradiaphragmatic presentation turned out to be an adverse prognostic factor with regard to disease-free survival, whereas it was not of significant independent prognostic value with regard to overall survival. Staging laparotomy in 11/35 infradiaphragmatic patients revealed 1 stage-IV case. The 34 remaining early stage patients were treated by irradiation plus combination chemotherapy (21 patients), irradiation only (9 patients), or combination chemotherapy only (4 patients). They were followed until death or from 4 to 171 months after initiation of therapy. With regard to disease-free survival, combined modality treatment (as opposed to radiotherapy only) was found to be of prognostic significance.