The steel corrosion on reinforced concrete members deteriorates their structural performance. In this study, an experimental investigation was conducted to examine the effect of corrosion degree on the flexural behavior of corroded reinforced concrete beams. Five shear-dominated RC beams, each with a cross-section depth of 200 mm, width of 100 mm, and length of 1,500 mm, underwent a three-point bending load test. Different corrosion degrees, ranging from 0 to 50% in one 12 mm steel rebar, were induced using the accelerated corrosion method. The test results revealed that the corrosion degree significantly influenced the flexural behavior. At a low corrosion, bonding of the reinforcing bar altered the shear failure to a ductile flexural failure. At a moderate corrosion, the redued rebar cross-section led to ductile flexural failure. However, a sharp drop in the ultimate load was observed with increasing corrosion degree, particularly larger than 40%. The flexural capacity of the corroded reinforcing steel beams was calculated using the reduced rebar cross-section aligned well with the test results.