High-strength heat-treatable aluminum alloy AA2219 finds application in aerospace industries. Though it has good weldability, with alternating current-tungsten inert gas welding, the joint efficiency obtained is only 40%, particularly in thicker plates. In the present study, an attempt has been made to improve the weld metal properties by modifying the chemistry of fusion zone and post-weld thermo-mechanical treatments. Fillers were made through casting route by melting conventional 2319 filler with Sc and Mg. Two levels of Sc (0.3% and 0.6%) and four levels of Mg (0.3% to 0.6%) were varied. Compressive deformation was done on the fusion zone of the weld to get three levels of percentage of reduction (4%, 8%, and 12%). As welded specimens and welds after compressive deformation, those were subjected to post-weld aging treatments at 190°C for different periods up to 100 h. Compressive deformation on the welds made with modified filler of 2319 with Sc and Mg resulted in significant improvement in the weld metal strength. © 2009 Springer-Verlag London Limited.