An experimental study was conducted to predict the flexural strength of corroded full-scale reinforced concrete (RC) beams. Two different concrete strength levels at two different steel ratios were tested for different corrosion levels ranging from 0 to 17%. An accelerated corrosion aging method was applied to corrode the reinforcing bars embedded in concrete. The actual corrosion levels were obtained by breaking the concrete and extracting the reinforcing bars. A practical model was developed for the prediction of the flexural strength of corroded RC beams. The developed model predicted the experimentally obtained flexural strength of corroded beams found in the literature well. The results revealed that the structural behavior of corroded RC beams requires consideration of the corrosion levels at both the tensile bars and the stirrups (which are more exposed to corrosion because of their use as outer reinforcing bars) and have significant effects on the flexural strength of corroded RC beams.