Modern building construction techniques sometimes involve the passing of pipes or ducts for water supply, electrification, and telecommunication through reinforced concrete beams to protect them against mechanical damages and add aesthetic value to buildings. This study looks into the effect of vertical circular openings on the flexural strength of the reinforced concrete beam. Two (2) sets of beam samples were investigated during this study: computer simulated reinforced concrete (RC) beam using ANSYS 19.1 and laboratory cast. The results of the flexural strength test conducted show the following: Reinforced concrete beam with vertical circular openings of diameter greater than 33.3 % of beam width (B) reduced its flexural strength by at least 20 %; maximum compressive stress of concrete occurs at the openings region of the beam; the difference in ultimate load capacity of finite element (FE) beam models and experimental beam specimen is 3.5 %. It can be deduced that ANSYS software is an appropriate finite element (FE) tool to predict the behaviour of RC beams. Hence, it is hereby recommended that the diameter of the vertical circular opening in RC beam should not exceed 33.3 % of the beam width and its location from beam support should not exceed L/6.