The paper is focused on the determination of the heat treatment effect on AW2099 welded joints properties. Laser beam welding was applied at constant welding parameters during the experiment. After the welding, solution annealing and artificial aging were applied at 150°C and 180°C for 24 hours. Subsequently, a static tensile test and microhardness measurement of welded joints were performed. The results of the tensile test showed that both heat treatment regimens resulted in an increase in the strength of welded joints and ensured an increase in hardness also in the area of the weld metal. The highest strength value (427.25MPa) was observed at a curing temperature of 150°C and a time of 24h.