The influence of concrete creep and shrinkage on the behavior of reinforced concrete elements is most often checked through the serviceability limit states: limitation of stresses, cracking and deflections. Under sustained load, the deformations of the element gradually increase with time and may be many times greater than the initial value. If the temperature remains constant, the gradual development of strain with time is caused by the shrinkage and creep of concrete. In order to determine the influence of different intensity of long–term sustained load on the behavior of reinforced concrete elements during the time, an experimental program has been realized. Eight reinforced concrete beams and an appropriate number of test concrete samples were made and monitored in a laboratory environment with constant ambient temperature and humidity. Seven beams are loaded with different load intensity, whilst six beams are loaded with a sustained load with intensity in which cracks appear in the considered time period. No load was applied to one of the beams and only the shrinkage strains of concrete were observed. Through the experimental analysis was obtained a picture of the long–term behavior of reinforced concrete elements subjected to different intensity of sustained load, as well as its influence on the serviceability limit states. A comparison was also made with the results obtained with modern analytical models in the codes.