Fifty-one cases of Hodgkin's disease, of lymphocytic predominance type, nodular subtype (HDLPN) were singled out from three sources: lymph nodes originally diagnosed as malignant lymphoma, nodes suspected of lymphoma and nodes suspected of toxoplasmosis. Two thirds of the 51 patients were men, and the median age was 42 years. The disease was characteristically unilocular and cervical and axillary nodes were most often involved. Local recurrences were common (in 13 cases). Oncological treatment (irradiation, cytostatics, or both) was given to 20 patients, whereas 31 patients remained untreated as the original histological diagnosis was not malignant. Despite the lack of treatment, the prognosis was good. Relative actuarial survival for the whole material was 93% at five years and 80% at ten years. During follow-up, five patients developed a diffuse large-celled non-Hodgkin's lymphoma 4-11 years after the onset of HDLPN. The majority of the subsequent lymphomas cannot be therapy-induced as only one of these patients had previously been treated (irradiated). Transition to other types of Hodgkin's disease was observed only in two cases. It is concluded that HDLPN is a clinicopathological entity with a good prognosis, but that it may sometimes change into a more malignant lymphoma of the Hodgkin's or non-Hodgkin's type.