This study discusses the model updating performed on a two-story reinforced-concrete masonry-infilled building using the dynamic response obtained during ambient vibration measurements. Five infills were demolished at four stages creating four damage states. The numerical model of the building is developed based on the obtained material properties and geometry. The model updating process minimizes a target function defined as the least-square optimization of an inverse eigenvalue problem. The reference model is then updated using the experimental results in each stage of damage to assess the damage. The dynamic properties obtained from the updated model match well their experimentally-estimated counterparts. Also, the model can reliably locate the damage introduced to the structure.