Poly (lactic acid) (PLA)/thermoplastic polyurethane (TPU) blends are very important for use in many areas, including biomedical applications such as medical sutures. Both polymers have biocompatibility, an extremely important factor in the production of materials for medical use. In addition, it is important that materials have antimicrobial properties so that there is no proliferation of pathogenic microorganisms in their application spot. The addition of carbon nanotubes (MWCNT) can induce this antimicrobial activity in the PLA/TPU blends. In this work, PLA/TPU blends based MWCNT nanocomposites were prepared by extrusion. The nanocomposites were characterized for thermal (differential scanning calorimetry and thermogravimetric analysis) and biological (agar diffusion test) properties to evaluate their application as antimicrobial materials for biomedical applications. The compositions 50/50 CNT and 60/40 CNT proved to be appropriate for the application, as they showed antimicrobial activity.