The increasing generation of urban solid waste is a major global problem. The amount and composition of waste is fully linked with the consumption profile of the population. Thinking about consumption, the use of coffee in capsules has grown in recent years for being a practical way of drinking coffee. However, the capsules aggravate the problem of urban solid waste, and in many places there is still no technology or adequate policies for recycling them. To reduce this problem, coffee capsules were used in the production of polymer blends containing thermoplastic starch and fibers from banana stalks as a reinforcing agent. The fibers were selectively added in the different phases of the blends, as a way to change the viscosity ratio between the phases of the blends, causing changes in mechanical properties. The results showed modifications in mechanical properties, depending on the concentration and phase to which the fiber was added, resulting from the change of phase morphology of the analyzed blends, pointing to a viable application of banana stalk residues and coffee capsules.