In the field of inflammation imaging, nuclear medicine techniques can be considered as a non-invasive tool to early detect pathophysiological changes in affected tissues. These changes usually occur before clinical onset of symptoms and before the development of anatomical changes, that are commonly detected by radiological procedures. This is particularly important for prognostic purposes, therapy decision making and for therapy follow-up. Here we review the current state-of-the art of nuclear medicine for diagnostic purposes in different conditions characterized by a chronic inflammation, such as vulnerable atherosclerotic plaques, vasculitis, rheumatoid arthritis, Sjogren syndrome, autoimmune thyroid diseases, inflammatory bowel diseases, Coeliac disease, Type 1 diabetes mellitus and other immunological diseases. Overall, we describe several different approaches based on radiolabeled cells, peptides and antibodies or FDG. It emerges the role of PET and of hybrid cameras in particular (SPECT/CT and PET/CT) for diagnosis of these disorders and for therapy decision making and followup.