A model describing thermal, metallurgical and mechanical effects of welding is developed for work-hardened aluminum alloys. It is based on thermo-mechanical constitutive equations of a generalised standard elastoplastic type which, in addition, account for a metallurgical parameter. This parameter is used to describe recrystallisa­tion kinetics of cold-rolled aluminum alloys and its effects on mechanical properties during welding. The constitutive relations are used in a fjnite-element code with a view to modelling metal inert gas (MIG) welds of 5086.H24 aluminum alloy plates. At each stage of the calculation, experimental verifications have been made to validate the numerical results : temperature, metallurgical transformations and residual stress fields. A good agreement between experimental and theoretical results (thermal cycle, width of heat affected zone (HAZ) and residual stresses) is obtained. The X-ray diffraction and incremental hole-drilling methods have been also used to measure residual stresses.