In this work, a review of knowledge relative to the reintroduction of spent mushrooms substrates in the elaboration of casing layers and base substrates for new cultivation cycles is presented. Firstly, their use in the preparation of casing substrates to induce fructification in Agaricus bisporus cultivation is considered. Aspects like the historical evolution and geographical distribution of their employment, the used formulations and the applied treatments are described in this area, at the same time that different factors that can influence on the agronomic behaviour are discussed. On the other hand, the use of these materials in the preparation of substrates for cultivation of different species of mushrooms is considered, taking into account aspects like their enrichment and combinations with other materials, the treatments to apply and the obtained results. These applications allow to integrate this type of materials by means of new formulations and methodologies with the added advantages of lowering the production costs and decreasing the environmental impact.