The phytases production by solid-state fermentation and their use in animal feed have become a subject of great interest. Solid-state fermentation provides several advantages over conventional enzyme production processes, and agro-industrial by-products can be put to use. The goal of this work was to study the utilization of different substrates by solid-state fermentation phytases production. The mediums were composed of orange pomace, castor bean cake and tung meal, different Brazilian agricultural by-products. The present results demonstrate the phytase produced by the same strain differ depending on the culture medium used. This conclusion was possible after the study of phytase produced by Paecilomyces variotii with three different culture mediums previously described. The highest phytase production were obtainment in tung meal studies, with 1.5 U/g substrate. The castor seed cake and orange pomace produced 0.26 and 0.08 U/g substrate, respectively. The three phytases produced were obtainment in 72h of incubation at 30 °C with 10 g of substrate and 10 mL of destilled water. One possible explanation for this phenomenon is that the use of different mediums used for the microorganism growth forces itself to adapt in these different sources of nutrients, thus showing distinct yield of production. Another possible explanation is that, the variance of components in each substrate can induce microorganism development in different ways, diverging the enzyme production. In conclusion, these processes has potential to be very important for the agro-industry in Brazil because these residues will be abundant and there are an emerging market for feed ingredients.