In the present paper, the results of an experimental research on the monoaxial and low cycle fatigue behaviour of butt-welded joints and cruciform specimens, relised from B450C Tempcore reinforcing steel, are presented. The objective of the research is to establish whether welding of Tempcore reinforcement may safely be adopted in seismic regions, with particular reference to the critical regions of reinforced concrete structures. The results show that butt-welding should not be permitted in plastic hinges, at least until a proper cyclic test procedure is codified, whereas properly performed spot welds between stirrups, and longitudinal bars may safely be applied.