Creep and creep rupture tests were carried out for friction-stir-welded (FSW) joints of 5052 aluminum alloy plates at temperatures between 573 and 723 K. The results were compared with those of the base metal. 5052-O plates of 20 mm in thickness were joined by FSW and round bar creep specimens were machined out of the welded plates. Tensile tests were also conducted at RT, 623 and 723K for both FSW joints and base metal. The tensile strength of the joints was almost the same as that of the base metal at room and elevated temperatures. However, the FSW joints showed appreciably higher minimum creep rate and shorter rupture time than the base metal at all the tested temperatures and initial creep stresses. Creep rupture of the joints always occurred within the plastically stirred zone with lower contraction of cross-sectional area. Thus, FSW joints of 5052 alloy plates showed lower creep strength than the base metal.