Creep behaviour of butt-welded thin Inco718 sheets is complex due to the presence of distortions during the welding process and the stress concentration caused by the weld bead fillet. This paper presents an experimental study and finite element analysis of creep of welded Inco718 specimens. Based on the elasto-plastic and creep finite element analyses, a creep rupture life estimation method for Inco718 welded sheets is proposed. The predicted creep rupture life of Inco718 welded sheets correlates reasonably well with the experimental creep rupture life.