The dissertation describes the results of an extensive experimental and analytical investigation into the effect of connections on the seismic response of precast concrete buildings, which was performed within the framework of the two European projects: SAFECAST and SAFECLADDING. The investigation was concerned with two important groups of connections, i.e. those between columns and beams, and those between the cladding panels and the main structure. Cyclic tests were first performed on specimens from both groups of connections, after which the failure mechanisms, based on the obtained experimental results, and making use of detailed 3D numerical analyses, were explained. A number of robust engineering models were developed, which take into account some of the key characteristics of the cyclic response of connections of the investigated types. In the case of dowel connections, the effect, on the load-carrying capacity of the connection, of stirrups, as well as of the large relative rotations between columns and beams, was investigated. This represents one of the main contributions of the dissertation. In order to evaluate the effect of connections on the seismic response of whole buildings, an extensive parametric study was then performed, which examined the fragility and seismic risk of typical singlestorey and three-storey precast buildings located in Ljubljana. It was found that if the load-carrying capacity of the dowel connections was inaccurately assessed, then the safety of such structures could be seriously affected, since the ability of connections of this type to dissipate seismic energy by means of plastic deformation is relatively low. In the case of the connections between the cladding panels and the main structure, it was shown that the probability of failure was, in the case when vertical panels are used, relatively high (between 2.0 and 30% over a period of 50 years), whereas in the case of horizontal panels it was significantly less (between 1.0 and 5.5%, or between 0.1 and 1.3%, depending on the type of connections used). Based on the new findings, guidelines were prepared for the design of beam-column dowel connections, and connections between cladding panels and the main structure. Dowel connections have to be designed according to the capacity design method, for which their load-carrying capacity needs to be accurately estimated. In this part of the dissertation some expressions for the calculation of this capacity are proposed. Methods which can be used to verify the adequacy of connections between facade panels and the main structure are also given. If the performance of such verification methods is infeasible, then second-line back-up devices, i.e. restrainers, need to be installed. The design, testing, and evaluation of the necessary load-carrying capacity of such systems are presented in the final chapter.