In the last decades, the solid-waste management related to the extensively growing production of plastic materials, together with their durability, have stimulated increasing interest in biodegradable polymers. At present, a variety of biodegradable polymers has been developed and has already been introduced onto the market. However, a noteworthy economical effort is still focussed in tailoring structural properties in order to further broaden the range of applications without impairing biodegradation. Improving the performance of biodegradable materials requires a good characterization of both physicochemical and mechanical parameters. Polymer analysis can involve many different features including detailed characterization of chemical structures and compositions as well as average molecular mass determination. It is of outstanding importance in troubleshooting of a polymer manufacturing process and for quality control, especially in biomedical applications. This book chapter describes recent trends in the structural characterization of biodegradable materials by modern mass spectrometry (MS). Furthermore, it provides an overview of the analytical tools used to evaluate their degradation. Several successful applications of MALDI TOF MS (matrix assisted laser desorption ionization time of flight mass spectrometry), ESI MS (electrospray ionization mass spectrometry) and SIMS (secondary ion mass spectrometry) for the determination of the structural architecture of biodegradable macromolecules, including their topology, composition, chemical structure of the end groups, and surface analysis have been reported. However, MS methodologies …