The corrosion behaviour of a AA2050T34-FSW was examined as a function of post weld heat treatment condition. Immersion tests in 0.1 M Nac1 and G110 intergranular tests were performed and the corrsion morphology and the depth of attacks in the different regions of the weld were investigated using FEG/SEM. Polarisation measuresments in the different regions of the weld and long term OCP for the full weld were taken and results were correlated with immersion test observations.