Finding the efficient strengthening and repair methods of reinforced concrete beam is necessary in terms of maintaining the safety of the structures for beam s under poor performance. Now a day engineered cementitious composite has been recently introduced for strengthening purpose of reinforced concrete structures to improve its deficiency . Engineering cementitious composite is an ultra- ductile cement- based material reinforced with fibers and it is characterized by high tensile ductility and tight crack width control. This study targeted to conduct experimental investigation on the flexural performance of reinforced concrete beams strengthen with lathe waste steel scrap fiber based engineering cementitious composite material. Three- face U shape jacketing was selected to improve the interfacial bond interaction of layered composite with substrate concrete. The Parameters considered was varying percentage volume of fiber in layering composite. Hence, lathe waste steel fiber having good tensile strength and good bonding is added in mortar matrix. This thesis comprises characterization of fiber, hardened cementitious composite, and the flexural performance of the layered reinforced concrete beams. The characterizations of fibered engineering cementitious composite on twelve small beam specimens and on twelve cylindrical specimens were conducted experimentally. And then, casting of fifteen reinforcing concrete beams having three as a reference beam whereas, the remaining twelve beams were strengthened using this composite. Jacketing thickness on reinforcing concrete beam was 25mm at bottom face and 20mm on two side faces. All beam specimens have been tested under center point load bending test. During testing of samples load- deflection history was recorded and finally load carrying capacity, crack pattern, mode of failure, energy absorption capacity, and ductility effect of strengthened beam was discussed. Test results showed that strengthened beams behaves improved flexural capacity up to 106.8% as compared with control beam and e nergy absorption capacity of strengthened beam was also improved by 2.58 times that of the control beam interface bonding performance between substrate concrete and the jacketed layer was good enough . Key words: Flexural Strengthening, Engineering cementitious composite, Lathe Waste Steel Scrap Fiber