Of 750 patients with stage I, II or III Hodgkin's disease, admitted to the University and Hospital Radiotherapy Divisions, Florence, between 1960 and 1981, 28 (3.7%) had involvement of Waldeyer's ring (WR). In 25 patients there was associated involvement of upper cervical nodes. Other factors associated with WR involvement were age over 55 years, lymphocyte predominant histological sub-type, uninvolved mediastinum, and size of involved upper cervical nodes greater than that of involved lower cervical nodes. These factors help to define indications for prophylactic irradiation of WR.