Among 387 cases of non-Hodgkin's lymphoma (NHL) treated in our units between January 1977 and December 1990, 52 (13.4%) had primary extranodal (PE) NHL of the head and neck. The median age was 55 years with a M:F ratio of 1.9:1. The most frequent primary site was the tonsil (28 cases), followed by oral cavity, parotid gland, orbit and other sites. The aggressive histological subtypes predominate. 55.2% of the patients were in stage I and 44.8% in stage II of disease. The CR rate was high (94.2%). The 5 years' overall survival rate was 65% and it was influenced mainly by stage (stage I 82.5% vs. 48.7% in stage II). Sex, age and histology did not significantly affect survival rate. Patients with primary Waldeyer's ring involvement (WR group) did not differ significantly from the other primary sites analyzed as a group (non-WR group) in respect to median age, sex distribution, histology and CR rates. They differed, however, in: (1) stage distribution with stage II disease more frequent in the WR group; (2) overall survival and disease-free survival both of which were significantly better in the non-WR group; and (3) the high incidence of GI tract involvement as initial manifestation of relapse in the WR group. It is concluded that the behaviour of the Waldeyer's ring PE-NHL is rather distinctive and should be considered separately from the other PE-NHL of the head and neck.