The invention relates to a method and a device for deforming a U-shaped electric conductor into a hairpin which can be used to produce a bar winding of an electric machine. Prior to the deforming process, the electric conductor has two parallel limbs which are integrally connected together by means of a connection limb, and the three limbs are arranged on an imaginary plane. According to the invention, the two parallel limbs are first clamped in a respective clamping device, the first limb together with the first clamping device is then held in place, the second limb is then moved away from the first limb on a circular path, thereby stretching the connection limb, and a deformation section of the electric conductor is simultaneously or subsequently moved on a guide surface of a twisting guide element, wherein the guide surface protrudes radially beyond the circular path.