Glycomics is an international project that analyses systematically and comparatively the overall and/or specific structural and biological properties of carbohydrates, also known as sugars or glycans, within a repertoire from a given type of cell, tissue, organism, kingdom, or even from a certain environment, as found under specific conditions. Glycomics is one of the latest omics projects to be launched into biology. This was because carbohydrates had been primarily considered as a mere class of structural or energetic molecules. Besides that, structural and functional studies in glycomics are more challenging than other projects, and analytical limitations in glycobiology have impaired the progress. However, with the development of technology, and mostly through recent scientific achievements, innumerous vital biological functions have been uncovered and attributed to the sugars. Moreover, certain glycans may also exhibit effective medicinal properties which have in turn awakened a great interest by pharmaceutical companies. This book compiles and illustrates some of these recent achievements concerning the principle examples of marine sugars with medical properties, such as chitin, chitosan, sulphated polysaccharides, and glycoconjugates. Their therapeutic actions are very broad since they comprise beneficial effects in many systems such as inflammation, coagulation, thrombosis, cancer growth/metastasis, and vascular biology. Additional information about the enzymatic synthesis, chemically modified derivatives, relevance of composing units, and other biochemical properties of these marine medicinal glycans are also discussed herein.