The magnetic domain structure in Co nanowires with dimensions x x y x z = 70 nm x 90 nm x 2 μm was examined by Lorentz microscopy and micromagnetic simulations. A slab of two collinear Co nanowires separated by Cu were produced from a sputtered and annealed 90 nm Co/180 nm Cu/90 nm Co trilayer by transmission electron microscopy preparation methods. The easy axis of magnetisation in the Co wires with a hexagonal, c-axis-textured grain structure is parallel to the y-direction. The magnetic domains are periodic and have a size of about 80 nm. A partially open closure domain pattern with tilted magnetisation was found by numeric simulation.