The results of an experimental program on seismic upgrade of slab-column connections are presented in this paper Two of the four slab-column specimens designed according to ACI 318-63 code provisions were upgraded by externally installed carbon fiber-reinforced polymer (CFRP) stirrups and the other two, designed and detailed according to the ACI 318-63 and ACI 318-02 codes, respectively, served as control specimens. Specimens were tested under constant gravity shear and lateral displacements were applied in a reversed cyclic manner Punching shear failure occurred for the control specimens at a lateral drift-ratio of approximately 2%. Upgraded specimens had significant flexural yielding and sustained deformations up to a drift ratio of approximately 8% without significant losses of strength. Punching failure was not observed in the upgraded specimens. In the upgraded specimens, displacement ductility increased by a factor of at least 2 and the joint rotation ductility factor increased up to 3.5 times that of the control specimen. The results of the experimental program showed that the proposed upgrade method is successful in increasing deformation capacity and avoiding brittle failures that can occur under high gravity loadings.