© 2009 International Institute for FRP in Construction (IIFC).Reinforced concrete (RC) wall application to the selected bays of the buildings has been the most common practice for the strengthening of RC structures in Turkey and elsewhere. Many experimental studies and the seismic performance of the structures rehabilitated by this way have already shown the efficiency of this method. However, rehabilitation through RC infill wall application requires evacuation o f the building during construction period. This issue makes it impractical for the huge building stock which needs urgent rehabilitation especially in seismic zones of high risk level. For this reason, development of innovative strengthening techniques which would not interrupt the use of the building during rehabilitation becomes imperative. Subsequently, a research project was initiated at M E T U Structural Mechanics Laboratory in 2001, which aimed to strengthen the existing masonry infill walls by means o f diagonal CFRP fabrics and to convert these walls into structural elements forming a new lateral load resisting system. In this study, which is a part of the former project, the main purpose was to investigate the effect of height/width ratio of the infills on the overall behavior attained by previously developed rehabilitation methodology. Eight 1/3 scaled 2-story 1-bay reinforced concrete frames were tested in the experimental part of the study and the results of these tests are summarized here.