Abstract: This paper deals with the strengthening of deteriorated reinforced concrete building by externally bonded carbon fiber composites. Four storied reinforced concrete residential building is selected for case study. It was constructed in 1992 and various deterioration symptoms are found. Static and dynamic analyses are performed by E-Tabs software using the various strength of members obtained from rebound hammer technique. The overstressed members are strengthened by externally bonded carbon fiber sheet. Experimental work for compression test on concrete cylinders externally bonded by carbon fiber sheets is performed. Compressive strength increment depends on the number of composite layers and percentage of wrap on concrete specimens. The required areas and thickness of carbon fiber wrapped sheet for the members are calculated by using Sika Carbodur FRP analysis software. For flexural strengthening, the maximum area required is 92 mm2, for shear strengthening and confinement the maximum thickness of FRP required are 0.35 mm and 0.18 mm respectively.