170 NHL children aged 1-14 [mean age 6] have been treated for the last 5 years. The diagnostic examination included the disease history, physical examination, bone marrow cytology, tumor histology (all patients), immunophenotyping (17 cases), x-ray and sonography of the chest and abdomen. According to the International NHL staging system, 35% of the patients had NHL stage II, 65% stage III or IV. The study entered 71 patients who underwent additional lactate dehydrogenase test, CT-scanning. 44 of them received nonprogrammed therapy on the basis of ACOP (group I), 27 patients were treated according to BFM-NHL-90 for B-, non-B- and large-cell anaplastic lymphomas (group II). The efficiency of the methods did not differ for patients at stage IIR. At the II NR stage complete remission (CR) was up to 41% in the group I and 60% in the group II. 50% of the children from group I and 20% from the group II were resistant to treatment. All the group I patients developed relapses, none got relapses in the group II. CR was observed in 64% and 78% of patients from group I and II, respectively, who had NHL stage III and IV. Relapses occurred in 41% and 14%, respectively. CCR was in 22% in the group I and in 67% of the group II patients. Effectiveness of B-NHL treatment according to BFM protocols was higher than in other types of NHL as to the number of relapses and frequency of CCR: the latter was 76% compared to 50% of non-B-NHL.(ABSTRACT TRUNCATED AT 250 WORDS)