The strengthening of reinforced concrete structures turns to be necessary due to a number of factors, such as: mistakes in the design or in the construction leading to unsafe structural systems; deterioration of concrete and steel caused by natural aging, aggressive agents or accidents like fire and shocks; the changing of the original use of the structure with the increase of loading and/or modifications in the geometry. The application of carbon fiber composites for strengthening of reinforced concrete structures is a very new and modern issue in structural engineering. The use of this material is very interesting due to its lightness, high mechanical strength, resistance to corrosion, electromagnetic neutrality, easy application and maintenance of the original shape of the structural element. The choice of this type of reinforcement, instead of more traditional systems using steel plates, depends on the economical viability and specific restrictions made in the project. The objective of this work is to develop analytical model for flexural design of reinforced concrete beams strengthened with carbon fiber composites. A literature review was carried out in order to obtain the experimental evidences on this subject. In order to evaluate the efficiency of the analytical model, the numerical results obtained with this model are discussed and compared with the experimental and numerical results obtained from literature.