A fiber-composite rotor blade, especially of a rotary-wing aircraft, with a predefined rotor blade profile that has a predefined outer contour of the profile, comprising a fiber-composite rotor blade structure having an upper and a lower cover skin and a profile core situated between them, and at least one highly extensible cable integrated into the fiber-composite rotor blade structure in the direction of the span of the rotor blade, whereby said cable can be connected to a functional device that can be attached onto or into the fiber-composite rotor blade structure. The cable is a highly extensible power and / or signal transmission cable, comprising at least one cable strand with at least one first cable core made of an electrically insulating, elastic plastic material, and at least one first cable wire that is wound around the first cable core at a predefined pitch angle, like a spiral and free of crossovers.