the aim of this paper is to present the results of four tests performed at imme to evaluate the effect of the number of vertical confining elements, called confining-columns in this paper, in the seismic behavior of confined masonry walls. the walls were tested under reversed cyclic lateral loads and constant vertical load. four full-scale walls of the same cross-section area were constructed containing two, three, or four confining-columns, as follows: specimen m1 consisted of one panel and two confining-columns; specimen m2 consisted of two panels and three equally spaced confining-columns; specimen m3 also consisted of two panels but the central confining-column was located at 1/3 of the wall length, and specimen m4 contained three panels and four equally spaced confining-columns. the results obtained show how the number of confining-columns affects the stiffness degradation, the energy dissipation capacity, the ductility, the cracking pattern, the deformability and the strength of the walls. these results will be useful to improve the recommendation for analysis and design of confined masonry wall structures to adequately withstand severe earthquakes.