Three hundred seven cases (244 gastric, 63 intestinal) of primary gastrointestinal non-Hodgkin's lymphoma (NHL) in stages EI and EII, according to a modified Ann Arbor system, were examined retrospectively. The histological classification for mucosa-associated lymphoid tissue-derived lymphomas was applied. Gastric NHLs (male-female ratio, 0.97; mean age, 64.5 years) were stage EI in 51% and stage EII in 49% of cases. Histological grade of malignancy was low in 41% and high in 59% of cases; all NHLs were B-cell type. Tumors were radically resected in 87%, and overall 2-, 5-, and 10-year survival rates were 61%, 55%, and 46%, respectively. Early lymphomas (substage EI1) had best prognosis (5- and 10-year survival rates, 90% and 70%, respectively). Intestinal NHLs (male-female ratio, 1.1; mean age, 54.4 years) were stage EI in 30% and stage EII in 70% of cases. Histology was low grade in 21% and high grade in 79%, and all but 11 cases were B-cell type. In 58% of cases, radical tumor resection resulted in overall 2- and 5-year survival rates of 44% and 24%, respectively. Major prognosticators for survival in gastric location were low-grade histology, low depth of infiltration, and low stage and radical resectability of lymphoma; all factors were strictly intercorrelated. In intestinal site, radical tumor resectability was highly significant for survival. Cumulative proportion of relapses after 5 years was higher in intestinal than in gastric sites (44% vs. 22%). In conclusion, primary gastrointestinal tract NHLs may represent an entity with respect to characteristic histological features, focal tumor growth, and potential cure by radical resection. Because of late relapses, clinical follow-up is needed.