The mechanical behavior of nanostructured metallic multilayers has been extensively investigated using nano-indentation or micro-pillar compression tests in recent years. However, relatively few studies have examined the mechanical behavior of multilayers via tensile testing, which provides the most accurate measure of mechanical properties such as modulus, yield strength and ductility. In this study, we examined the mechanical properties of a Cu/Co nanocomposite multilayer film (4 nm layer thickness of Cu and Co), sputter-deposited at room temperature, using MEMS-based tensile testing. XRD analysis of the film showed a strong (111) texture, with the peak position corresponding to a d-spacing that was the average of the d-spacing of FCC Co and FCC Cu. The film showed a high yield and fracture strength of 1.15 GPa and 1.4 GPa, respectively and also exhibited notable inelastic strain recovery, both during and after unloading. We also co-deposited a Cu-Co film with the same composition at room temperature using magnetron sputtering. XRD analysis of the co-deposited film revealed a FCC solid solution with a (111) texture, even though Co and Cu are expected to have little miscibility at room temperature. Interestingly, no phase separation was seen in the co-deposited film even when it was annealed at 400 oC. However, phase separation occurred at 600 oC, with the formation of FCC Co and FCC Cu. Tensile testing was performed on these co-deposited, solid solution and phase separated films to compare their properties with those of the nanocomposite multilayers.