A semiconductor memory device including a substrate, a first element isolation film pattern, and a second element isolation film pattern. The substrate includes a first region and a second region. The first element isolation film pattern is in the first region and corresponds to a first active region. The second element isolation film pattern is in the second region and corresponds to a second active region. The first element isolation film pattern includes a first material and the second element isolation film pattern includes a second material different from the first material.