Strengthening reinforced concrete bridge girders with Carbon Fiber Reinforced Polymer (CFRP) laminates has increasingly been used. This research investigates the effectiveness of using CFRP laminates in flexure strengthening of girders. Three sets of girders have been tested. The first two sets composed of 11 girders were experimentally tested to failure. The third set of girders was pre-cracked before installing the CFRP and testing. A 100 kips capacity displacement-controlled hydraulic actuator ram was used to apply static loading at mid-span. The results were analyzed for the flexural behavior of the strengthened girders including load-deflection, mode of failure, and possible debonding or delamination of CFRP. The results indicated a significant gain of 41.9% to 89% in the flexural capacity of the first two sets of strengthened girders than that of control ones. The third set showed a restoration of flexural strength for the repaired precracked girders. The study covered key parameters such as the number of CFRP layers and using U-shaped laminates.