Finite element analysis and neutron diffraction were used to evaluate the radial, axial and hoop residual strains in a thin walled pipe with autogenous laser butt girth weld. The pipe, 50 mm inside radius and 2 mm in thickness, was made of AISI 304 stainless steel. Laser welding was carried out using a 2700 W laser, with helium as shielding gas. The results from the numerical and experimental methods were compared.