The distribution of histologic subtypes of non-Hodgkin's lymphoma (NHL) in children is known to differ from that in adults, but the histologic characteristics of NHL in very young children have seldom been investigated. The authors retrospectively studied 331 patients with NHL, of whom 16 were younger than 3 years old and found that the distribution of histologic subtypes in the very young patients was similar to that in older children. Six patients had small noncleaved cell lymphomas, five diffuse large cell immunoblastic, four lymphoblastic, and one had a diffuse large noncleaved cell lymphoma. The complete remission rate was 62.5% and six (37.5%) patients are long-term disease-free survivors, although remissions in the six children with large cell lymphomas were relatively brief, lasting no more than 7 months. These cases illustrate that NHL should be included in the differential diagnosis of tumors in infants and young children and that the distribution of histologic subtypes is similar to that in older children.