Abstract: Values of ¹¹¹In-octreotide and ⁹⁹Tc^m-NeoTec in tumor diagnosis are briefly reviewed. There are great values in diagnosis and follow up for patients with carcinoid tumor, medullary cancer of thyroid, and neuroendocrine tumors from pancreas or upper respiratory tract.Somatostatin receptors are also distributed in organs outside the classical neuroendocrine tissues. Positive studies are also found in patients with differentiated cancer of thyroid whose tuor have lost iodide concentrating ability, exophthalmos in Graves' disease or granulomatous process in sarcoidosis. The successes of tumor imaging with labeled somatostatin analogues have led to the development of radionuclide therapy for these tumors with the labeled analogues.The technics in labeling of somatostatin analogues have also led the expanded interests and studies of other peptides in molecular imaging.