Nuclear Medicine has greatly contributed to the diagnosis and treament of neuroendocrine neoplasms. This issue of PET Clinics will focus not only on the diagnosis and treatment of neuroendocrine tumors, but also theranostics. Topics include SPECT and other PET tracers, F-DOPA, Ga-DOTA-peptides, Yttrium- and Lutetium-based therapy, and the role of FDG PET. It also covers key information of theranostics.