Eighty seven cases of primary non-Hodgkin's lymphoma of the thyroid presenting to the Beatson Oncology Centre were reviewed. Stage IE and Stage IIE disease accounted for 79 of 87 cases. In a univariate analysis the presence of dysphagia, dyspnoea, positive nodes, stage or male sex all had a statistically significant detrimental influence on survival. Stage and dysphagia were the most influential individually and a multivariate analysis indicated that the prognostic information in all these features was essentially captured by just these two. A prognostic scoring index based upon stage of disease and the presence of dysphagia has been developed. Overall 5 year survival was 43%. Five year survival for Stage IE patients without symptoms of compression was 74%. Patients who underwent surgical resection of tumour followed by local irradiation appeared to survive longer than patients managed by irradiation without surgery, although after adjustment for prognostic features this advantage was not statistically significant.