This paper describes the measurement of longitudinal residual stresses within specially designed 200x180x25mm groove weld specimens. The purpose of these measurements was to compare the residual stress field arising from single and multi-pass weld beads laid down within the constraint of a groove in order to validate finite element simulations of the welding process. Measurements were made over the cross section at the mid-bead length, utilising the relatively new Contour method and neutron diffraction. Results from these measurements indicate a larger peak tensile longitudinal residual stresses within the weld region of the multi-pass weld sample. Good agreement is found between both techniques.