This study presents the results of residual stress characterization by neutron diffraction and the contour method on 13%Cr–4%Ni welds made using 410NiMo weld filler metal. The transverse, longitudinal and normal components of stress were determined by neutron diffraction. The longitudinal stress distribution was also measured by the contour method. The last bead of the weld was found to be in a state of triaxial compression while a part of the heat-affected zone as well as a region beneath the weld were in a state of longitudinal tension. These results are explained with reference to the low martensitic transformation start temperature (M_s) of the alloy. The same measurements were made on an identical weld that had undergone a standardized post-weld heat treatment. The maximum tensile stress was reduced from 534 to 136MPa, and the maximum compressive stress was reduced from 371 to 152MPa.