Osteosarcomas are tumors with a high aggressivity which gives early and frequent pulmonary metastasis. These patients have a poor prognosis. The reveal of prognosis factors and early detection of pulmonary relapse would influence the outcome of these patients. We performed a retrospective study at Oncology Institute from Cluj, observing 35 patients with osteosarcomas and pulmonary metastasis at the onset or in evolution. We tried to quantify some prognosis factors. We observed the predominance of male sex (20), from urban area (25), with age between 11-20 years (16 cases), with primary tumors localized more frequently at the limbs. Pulmonary metastasis were shown without free interval from the onset (12 patients), or in the first years (17 cases), more frequently with multiples locations (26 cases). 28 patients were submitted to surgical treatment for cure of primary tumor, 18 chemotherapy, and pulmonary metastasis resection in 5 cases only. The outcome under treatment was favorable in 4 cases only, compared with other studies. Early detection of pulmonary metastasis and aggressive therapy with augmentation of resection criteria for pulmonary metastasis would improve the prognosis of this patients.