Although they are classified as nonstructural elements, infill walls in reinforced concrete buildings are considered critical because they affect structural behavior and performance. Therefore, the identification of the mechanical properties of infill walls is important. This study performs code-based experiments to identify the mechanical characteristics of infill walls in a reinforced concrete building and evaluates the results on the basis of the dynamic behavior of the building. The compressive strength, modulus of elasticity, and initial shear strength of the infill walls, made of horizontally tiled bricks and cement mortar, are determined by testing wall specimens extracted from an existing building and are incorporated into the numerical analysis to determine dynamic properties of the building. The obtained dynamic properties are compared to those derived from the operational modal analysis. A modification is required in the modulus of elasticity of infill walls to confirm the building's dynamic behavior. The identified modulus of elasticity of the infill walls proves the reliability of the vibration survey as a tool to evaluate mechanical properties of infill walls in reinforced concrete buildings.