The pathologic and clinical features of 31 cases of childhood non-Hodgkin's lymphoma (NHL) were reviewed retrospectively using Rappaport's classification and a modification of the Ann Arbor staging system. Twenty-nine (93.5%) of the patients had diffuse and 2 (6.5%) had nodular lymphoma. Diffuse histiocytic lymphoma accounted for 10 cases (32.3%), diffuse undifferentiated for 9 (29%), and diffuse lymphocytic, poorly differentiated for 5 (16.1%). Five cases (16.1%) were unclassifiable. No cases of well-differentiated lymphocytic or mixed cell lymphoma were found. A modified classification was attempted, which included also large basophilic cell (LBC), convoluted T-lymphocytic (CTL), and Burkitt's lymphomas. These pathologic subgroups accounted for 35.4%, 16.1%, and 6.5% of the cases, respectively. The patients were almost equally divided between clinically localized and generalized stages, and their survival was stage-dependent. The overall survival was 32.3%; the 3-year survival was 50% for Stages I and II, compared to 7.7% for Stages III and IV. The gastrointestinal tract was the most common site of origin. In 22% of the cases, the disease originated in extra-lymphatic tissues. Central nervous system involvement occurred in 10 of 31 children (32%), and a leukemic picture developed in 6 of 31 (19%). The CTL lymphomas were confined to the mediastinum, whereas the LBC lymphomas arose mostly in Waldeyer's ring and Peyer's patches. We conclude that the extent of the disease as determined by clinical staging has prognostic significance in childhood NHL. The prognostic value of the histological classification could not be clearly established from our data.