Abstract <p>Inorganic polyphosphates (polyPs) are universal regulatory compounds and participate in the control of gene expression, stress adaptation, membrane transport, and cell motility. They play an important role in bone tissue development, thrombosis and inflammation processes, signal transmission in nerve cells, and amyloid formation. These polymers participate in phosphorus homeostasis in both living cells and natural and technogenic ecosystems. PolyPs are used as fertilizers, food additives, and water treatment compounds and flame retardants. Modern, highly sensitive, and specific methods for polyP analysis are necessary for solving fundamental problems for regulation of biochemical processes and for a number of practical tasks, such as monitoring the state of environmental objects, food quality, and developing new methods for treating bone diseases, the cardiovascular system, and neurodegenerative pathologies. Currently, efficient and highly specific methods for polyP assay have been developed, such as special extraction methods, enzymatic analysis, electrophoresis, DAPI staining, and microscopic methods, including micro-X-ray analysis. NMR retains its importance, especially for determining the polymer chain length. In this review, we consider polyP analysis methods from the point of view of problems solved in the study of various biological objects, with special attention to the most modern and widespread approaches.</p>