Cracks in reinforced concrete (RC) should be repaired if they present the potential for durability related problems such as corrosion of reinforcing steel. One way to repair extensive cracks is the use of epoxy injection. Another repair technique to enhance shear or flexural strength in deficient RC members is the utilization of externally bonded carbon fiber reinforced polymer (CFRP) fabrics. the effect of environmental conditioning on crack injection with or without CFRP strengthening is of interest in this investigation. Test results showed that the crack injection provided an increase in initial stiffness for un-strengthened RC beams. an increase in initial stiffness and ultimate strength was achieved in CFRP strengthened RC beams. Surface roughness combined with crack injection significantly increased the flexural capacity of the specimens. Environmental conditioning significantly affected the bond performance of the epoxy injection. the presence of sustained load during environmental conditioning resulted in reduced section capacity and ductility.