Abstract: Melt-extruded guides for peripheral nerve repair based on PU were realized. Various in vivo tests were carried out for the repair of medium (2.0 cm) size defects in the peripheral nerves of Wistar rats. Results from in vivo tests were subjected to histological examination after 1-3 months postoperative. Regeneration was found. Electromiographical analysis also evidenced functional recovery after 6 months from implantation. The research showed that PU guides can be used for the successful repair of small and medium size nerve defects with possible improvements by suitable bio-mimetic coatings.