Brazil, one of the largest agricultural producers in the world, has managed in recent years to significantly improve its production. However, in response to this advance in the agro-industrial sector, the generation of agro-industrial residues or sub-products has also increased, and its improper disposal may have a strong environmental impact, in addition to causing losses of raw materials and energy. In this context, the use of these residues as substrates for the production of high value-added compounds using semi-solid fermentation has been studied. Thus, the aim of this study was the physical-chemical characterization of pineapple and guava residues and their potential reuse in semi-solid cultivation. The results show that both residues are sources of bio-usable nutrients after a number of operational parameters of the bioprocess of choice are adjusted.