The aim of this study was to assess the efficacy and safety of targeted radionuclide therapy with [90Y-DOTA0, Tyr3]-octreotide (90Y-DOTATOC) in patients with metastatic neuroendocrine tumors. One hundred and sixteen patients with metastatic neuroendocrine tumors were included. All patients were pre-therapeutically staged with morphological imaging procedures and with somatostatin receptor scintigraphy. The scintigraphy was positive in all cases. The patients were treated with 162-200 mCi/m2 body surface. In 57 patients, the quality of life was assessed with the National Cancer Institute grading criteria (NCI-CTC). Restaging was performed 8-12 weeks after the last treatment cycle. Blood samples were drawn every 2 weeks after the treatment to evaluate toxicity. Complete remissions were found in 4%, partial remissions in 23%, stabilization in 62% and progressive disease in 11%. A significant reduction of symptoms was found in 83%. No serious adverse event occurred and the toxicity was acceptable. 90Y-DOTATOC is a safe and effective treatment for patients with metastatic neuroendocrine tumors.