Most current standards that are concerned with the seismic design of buildings do not provide sufficiently clear information about safety against collapse. For this reason a new procedure for the risk-based seismic design of buildings is proposed, which is iterative and based on the use of nonlinear methods of analysis. The proposed design procedure starts by the selection of an initial structure, which is gradually adjusted by means of iterations until the estimated seismic risk is lower than the target risk. Since the number of such iterations may become excessive, simple guidelines have been developed for the structural adjustment of reinforced concrete frame buildings, which can be used to improve the building's strength and deformation capacity by appropriately adjusting the structural elements selected on the basis of the results of pushover analysis from the current iteration. The concept of differentiation in the reliability of design is also implemented, so that less demanding analytical methods are used in the initial iterations, whereas more demanding, and usually more accurate methods are used to verify the design results obtained by using simplified methods. Part of the research was aimed at the improvement of the accuracy of seismic risk estimation, which is an important component of the proposed design procedure. New equations for seismic risk assessment, which take into account the physically defined limits of ground-motion intensity, have been derived. It was found that sometimes, if the lower and upper limits of the ground-motion intensity are insufficiently taken into account, overestimated values of the seismic risk may be obtained. The suitability of the proposed design procedure, which takes into account the newly developed equations for seismic risk assessment, was demonstrated on two examples of reinforced concrete frame buildings, one having 8 storeys and the other 15 storeys. The target risk was achieved after only four and three iterations, respectively, even though their corresponding initial structures had been only roughly defined. Taking into account the upper bound of the seismic intensity can result in a reduction in the estimated probability of collapse, which can in turn have a significant effect on the final design of the structure.