At the National Research Institute of Mother and Child, 158 patients, aged 3 to 21 years were treated for osteosarcoma, in the period 1985 - 1994. Metastases were found in 34 persons. Localisation of metastases: lungs - 32 cases, lungs and additionally bones - 6 cases, CNS - 1 case, bones without pulmonary changes - 2 cases. Chemotheraphy (acc. to different programmes) was the initial treatment. When stabilization or partial regression was observed, operative procedures were undertaken. In the case of progression, conservative treatment was used; changing chemothrapy protocol, or using palliative treatment. Following surgical procedures were made: thoracotomy - 8 cases, sternotomy - 5 cases, excision of bone tumour - 2 cases, laminectomy - 2 cases, excision of CNS tumour - 1 case. In the group of 18 patients where conservative treatment only was used, 2 children are alive. In the group of 16 patients where surgery was performed, 9 are alive. The authors suggest that in case of osteosarcoma it is profitable to extract metastatic foci in the period of stabilization after chemotherapy. It appears important to excise the metastatic foci even 2-3 times as this considerably prolongs survival in these children.