Tumours of the tonsillar area are defined as those arising in the tonsil proper or the tonsillar pillars and spreading to involve any part of the contiguous soft palate, tongue, buccal mucosa, and lateral pharyngeal wall. The thesis of this paper is that failure to control spread into the tongue is the most common cause of defeat in treatment of cancer of the tonsillar area. Two hundred and sixty-three cases of epithelial cancer of this region were seen at the Ontario Cancer Institute in the years 1921 to 1959 inclusive. Only the lymphomatous and recurrent cases have been excluded. Two hundred and sixteen cases are available for five-year analysis. Males are more commonly afflicted than females, by a ratio of 7 to 1. The tumour is one of later life, having a peak incidence at about sixty-five years of age. An anatomical classification has been adopted, since it is felt that this bears a closer relation to prognosis and treatment than does classification by size. Six anatomical subdivisions are recognized: 1. Tonsil proper 2. Tonsillar pillars 3. Base of tongue 4. Soft palate 5. Pharyngeal wall 6. Bilateral Cases have been allocated to one or other of these subdivisions on the basis of predominance of tumour spread. Classification of lymph node involvement has been simplified into two categories—unilateral and bilateral. Figure 1 shows graphically the tonsillar area, its various subdivisions, and the incidence of primary involvement. The incidence of lymph node invasion and distant metastases is also indicated. It is evident from this that the invasions of the base of the tongue and the lymph nodes are the salient features. In Table I, the pathological subdivisions, incidence of lymph-node involvement, and gross five-year survival rates are presented. It is interesting to note that the undifferentiated tumour is associated with a high incidence of lymph-node involvement, but carries a more favourable prognosis than the squamous-cell group. One of the two patients with salivary-gland tumours had a mixed salivary adenoma and died of extraneous causes in less than five years. The other, with a mucoepidermoid carcinoma, has survived five years, but with some doubt about the control of the disease. Since the majority of tumours of this region are squamous-cell carcinomas, and carry the most serious prognosis, the following remarks refer mainly to that type of tumour. In Table II the cases have been rearranged to show survival by site, demonstrating that, of the three most common sites or areas of involvement, invasion of the tongue carries the worst prognosis. When the problem of recurrence of the primary tumour is considered, a distinct pattern is seen. This pattern is shown in Table III for the cases in which sufficient information was available to make such an evaluation. This emphasises the problem of persistence of tumour in the tongue after initial treatment or of recurrence following apparently successful treatment.