Scintigraphy with single-photon radionuclides is a useful means of detecting various functional abnormalities in organs affected by IgG4-related disease (IgG4-RD). Notable examples include 67Ga to depict the inflammatory activity associated with IgG4-RD, salivary gland scintigraphy to delineate the degree of salivary gland injury, and renal scintigraphy to quantify changes in blood flow and functional impairment in the presence of renal lesions. In particular, 67Ga scintigraphy is a modality that detects systemic inflammatory changes and can be used to evaluate the activity of lesions within the pancreas, lung, kidney, salivary gland, and lymph nodes. Current use of the combined system of single-photon emission computed tomography (SPECT)-CT can further facilitate localization of regions in which abnormal accumulation of 67Ga is observed. Scintigraphic findings are not specific for the lesions of IgG4-RD. Thus, the main roles of this imaging modality are to clarify the degree of inflammatory activity, to determine the extent of organ injury, and to assess the effect of therapy by comparing studies before and after treatment.