Hydrogen storage can be broadly categorized into physical storage and chemical storage. The physical storage of hydrogen is constrained by the boundaries of a storage medium, such as storage tank or storage vessel. The difference is that the hydrogen in the physical method of storage does not interact with the storage media. In the chemical method of hydrogen storage, the hydrogen atoms or molecules interact with the material used for storage. The class of adsorption-based materials forms a weak Van der Waals bond with high surface area materials. The fundamentals of adsorption-based storage and some of the materials used for hydrogen storage are discussed in this chapter.