In Turkey, structural elements are strengthened with fiber polymer (LP) that causes a considerable increase in load bearing capacity and ductility system in order to exemplify a necessary and sufficient performance under lateral loads. In this study, nonlinear analyses of reinforced concrete beams retrofitted with LP material are performed by using nonlinear finite element (FE) method. Considering the laboratory tests done by Pham and Al-Mahaidi, finite element models of the beams are created in the ANSYS program. The mechanical properties of the CFRP (Carbon Fiber Reinforced Polymer) material used in the experimental studies in the literature have been tested in accordance with ASTM D7522 standards. According to the results of the laboratory experiment, the CFRP system was modeled mathematically and reinforced concrete beams were analyzed under static loads. The load-displacement curve results obtained from the FE analyses and the experimental data showed good match. After verification of the FE model, some parametric studies were investigated to evaluate the behavior of the reinforced concrete beams with CFRP materials. CFRP width along the bottom side of the beams, the number of layers in the CFRP system and the heigth of the materials applied along the front and back surfaces of the beams were varied in the analyses. Load capacity, the maximum stress-strain curve results on the concrete fibers along the bottom side of the beams, strain values on the CFRP system under the maximum load and the stress-strain values along the longitudinal reinforcement were obtained from the FE parametric analyses. The results showed that when the CFRP width increases the load capacity of the beam increases. Models indicates that if the CFRP layers are increased the load capacities are enhanced up to 6% and 16.5% on the beams with 3 layers and 4 layers, respectively. In the beams with CFRP systems along the front and back surfaces, the load capacities are improved by 27%, 33% and 36% when the CFRP heights on the surfaces are 86 mm, 130 mm, and 172 mm., respectively. Stress-strain curves obtained from the FE analyses reveals that the concrete strain values on the tension side of the beams are increased by the increment on the width of the CFRP system. Although, the strain values on concrete fibers are decreased with the increase in CFRP layers and the height along the surfaces. In the FE models, the CFRP strain values are determined under the maximum load and compared with the values according to ACI 440 standard. The results indicates that the strain values are well beyond the fracture strain limit. Therefore, the CFRP system were ruptured from the bottom face of the beam as obtained during the laboratory testing. The stress-strain curves of the longitudinal reinforcement are evaluated for each parmetric analyses. The stress values are decreased by the increase in the CFRP width, number of layers and the CFRP height along the faces. This case showed that the CFRP system contributed to the tension capacity of the beams and the ductility of the beams were decreased.