The objective of this work was the proportion and size of cane bagasse fiber in the physical (density and thickness), mechanical (flexural strength and tensile at break) and thermal (TG and DTG) properties of trays made from sweet potato starch. A fiber size of 75-45 μm and a 2.5% ratio allowed to obtain trays with low thicknesses and densities, but with more compact structures that improved the mechanical properties of trays made from sweet potato starch alone. In addition, higher thermal stability and lower decomposition rate are shown for trays with fiber size 75-45 μm and ratios of 2.5% and 5%. These results show that the smaller fiber size improves the properties of the sweet potato starch trays and that these trays can be used to replace the expanded polymer (EPS) for use in dry foods.