Cu80Co20/CNT nano-composites were prepared by mechanical alloying for various duration of time. The effects of CNT addition on Co solid solubility in Cu morphology, magnetic and electrical characteristics of the samples were analyzed using state-of-the-art methods, such as x-ray diffraction (XRD), differential thermal analyzer (DTA), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), superconducting quantum interference device (SQUID) and four point probe technique, respectively. In a sample that was milled for 10 h, it was demonstrated that the solid solubility of Co in Cu increased to 20 wt.%; however, CNTs in Cu80Co20/CNT nano-composites prevented this from happening. 10 h after mechanical alloying, CNTs were uniformly dispersed throughout the metal matrix, and the resulting products were agglomerates of nanoparticles. The addition of CNTs changed the magnetic properties of nano-composite samples, according to analysis of magnetic hysteresis loops. The saturation magnetization and coercivity of composite samples increased with increasing CNT content because of the non-dissolved paramagnetic Co in nano-composites and the exchange coupling phenomenon. Cu-Co/CNT nano-composites' electrical resistance increased with CNT concentration.