A power transmission belt and a method for manufacturing said belt. The belt includes: a backing layer made of a material with elastomeric behavior; a ventral layer made of a material with elastomeric behavior; a mechanical reinforcement means inserted between the backing layer and the ventral layer comprising a film with thermoplastic transformation surrounding the mechanical reinforcement means, said film comprising at least: a first component physically and/or chemically bonded to at least one component of the backing layer; a second component physically and/or chemically bonded to at least one component of the mechanical reinforcement means; and a third component physically and/or chemically bonded to at least one component of the ventral layer. The method for manufacturing said belt may advantageously use an anti-sticking means.