Growth impairment is one of the most important late sequelae in childhood malignancies. In the last few years, the contribution of cytotoxic agents to growth retardation has been a subject of investigation. The aim of this study was to evaluate the growth impairment in children treated for non-Hodgkin's lymphoma (NHL). The study group comprised 41 children ( eight girls, 33 boys) treated for NHL with three different chemotherapy protocols. All patients were in remission at the last visit. The control group consisted of 41 healthy age- and sex-matched children. All patients' standing heights and body weights were measured regularly from the time of diagnosis. Growth parameters were measured both at the time of diagnosis and at the end of treatment ( median treatment time: 6 months). Height and weight velocities were calculated at 6 month intervals after the diagnosis until the last visit. The mean height SDS of the patients was -0.66 +/- 1.42 at the diagnosis and 0.29 +/- 1.21 at the last visit. Height SDS of the patients showed a significant improvement at the end of the 2nd year after the diagnosis ( p = 0.005) and at the last visit ( p = 0.022) ( median follow-up time: 48 months after diagnosis). The height velocity SDS increase at the end of the 2nd year was particularly remarkable in short-term protocols such as BFM-90 B-NHL. The sitting height, the sitting height/height ratio and serum insulin-like growth factor-I (IGF-I) levels were found to be lower in the patients than those of control group at the last visit. One can conclude that chemotherapy might cause a reduction in growth velocity during treatment. The cumulative dosages of anti-neoplastic agents and serum IGF-I levels could have been implied in the pathogenesis of growth retardation.