The safety and serviceability of RC structures are time-dependent due to degradation phenomena, therefore assessing the fulfillment of required levels of safety and serviceability up to the end of the design working life of the structure is particular important. Among the most frequent environmental attacks affecting RC structures, reinforcement corrosion is considered the most dangerous source of degradation, which may occur only after depassivation due to carbonation of concrete cover, penetration of chloride ions, or a combination of both. In this paper, the effects of rebars corrosion on seismic response of RC structures were presented. A case study was analysed using time history analyses, in sound as well as damaged conditions, assuming a moderate corrosive attack. The outcomes were discussed in terms of displacement time history curves and acceleration time history curves. In addition, the interstory drift obtained form time history analyses was compared and discussed with the limit value provided by Code for seismic design of building.