The paper studies the influence of the service life on the microstructural and elastic-plastic properties of individual aluminum and steel wires depending on their location along the cross section of the AC120/19 steel-aluminum wire. It was found that aluminum wires in the outer layer, after long-term operation of 33 years, show integral density significantly lower than in the inner layer, which is associated with a significant effect of atmospheric conditions on the degradation of the surface of single wires. In new unused wires, all aluminum wires are characterized by a higher integral density, the same for all layers. The integral density of steel core wires in contact with aluminum wires, after long-term operation, shows values that are lower than the density of the central wire of the steel core that does not have contact with aluminum wires. In contrast to aluminum wires from the inner layer, aluminum wires from the outer layer in contact with the surrounding atmosphere have reduced values of Young’s modulus compared to a new unused cable. In comparison with the new cable, a decrease in Young’s modulus and an increase in amplitude-independent decrement values were found for steel wires from the cable core.