A method of manufacturing magnetoresistive random access memory (MRAM) device includes forming first and second patterns on a substrate in an alternating and repeating arrangement, forming a first capping layer on top surfaces of the first and second patterns, and removing first portions of the first capping layer and a portion of the second patterns thereunder to form first openings exposing the substrate. The method further includes forming source lines filling lower portions of the first openings, respectively, forming second capping layer patterns filling upper portions of the first openings, respectively, and removing second portions of the first capping layer and a portion of the second patterns thereunder to form second openings exposing the substrate. Then, contact plugs and pad layers are integrally formed and sequentially stacked on the substrate to fill the second openings.