We have produced arrays of Co nanowires in anodic porous alumina filters by means of electrodeposition. The structure and magnetization behavior of the wires was investigated with nuclear magnetic resonance ͑NMR͒ and magnetization measurements. NMR shows that the wires consist of a mixture of fcc and hcp texture with the ͑0001͒ texture of the hcp fraction oriented preferentially perpendicular to the wires. The magnetization direction is determined by a competition of demagnetizing fields and dipole-dipole fields and can be tuned parallel or perpendicular to the wires by changing the length of the wires.