The structural behavior of steel plate girders with web opening is investigated in this study. An experimental and theoretical investigation of plate girders with different types of openings in the web was conducted. Two types of web opening is investigated (square & circular) opening. The experimental work included testing of seven plate girder specimens under two point loads. Three specimens were tested to observe the influence of the circular web opening. The influence of the presence of square web openings was studied by testing other three specimens. While the last one was tested without opening as a reference (control) specimen. These specimens had the same dimensions. From experimental results the ultimate load of girders decreases with increasing opening size, and the position of plastic hinge depends on the size of hole A nonlinear 3D finite element model was deveioped using FE program ANSYS to validate the experimental results Four- nodes shell element (SHELL 181) was used to represent the steel plate. The proposed finite element model was used to study the effect of web slenderness on shear resistance of plate girder with web opening. Equation was suggested to predict the shear resistance. The analysis study give good agreement with experimental work.