A magnetic memory device includes a conductive line that extends in a first direction, and a magnetic track line that extends in the first direction on a top surface of the conductive line. The conductive line may include a first region having a first width in a second direction, and a second region having a second width in the second direction. The first direction and the second direction are parallel to the top surface of the conductive line and are perpendicular to each other. The second width may be greater than the first width. The magnetic track line includes first domains arranged in the first direction on the first region of the conductive line, and second domains arranged in the first direction on the second region of the conductive line. A size of each of the second domains may be less than a size of each of the first domains.