The restoration of strength and stiffness of damaged reinforced concrete beams with deficient reinforcements, through retrofitting, was experimentally and numerically studied. Retrofitting is carried out by wrapping glass fiber strips using cement-based composite binders. Six beams of size 1500mm (length) x100mm (width) x 150mm (depth) have been tested in four-point bending. Three beams are used as reference beams, whereas the other three are cast as shear deficient beams and loaded up to first few cracks.The damaged beams were repaired, cured and retrofitted. Flexure test is carried out to find the average ultimate load, maximum deflection, maximum moment, stiffness, energy absorption and crack pattern of reference and preloaded retrofitted beams. Numerical analysis is carried out for the similar shear deficient beams. It is concluded that the ultimate load and moment carrying capacity were restored in preloaded retrofitted beams. The stiffness and energy absorption are improved in preloaded wrapped beams with deflection at ultimate load being reduced.