Influence of annealing temperature on b-(Al 3 Mg 2 ) phase precipitation and corrosion properties of sensitised Al-6.8 wt% Mg alloy is investigated. Sensitisation of specimens annealed at 320 8C results in IGC and SCC susceptibility. Microstructural characterization shows fine precipitation of Mgrich phase forming nearly continuous film at grain boundaries, despite small precipitated fraction (0.5%), and grain boundary faceting. Sensitised specimens annealed at 265 8C are IGC susceptible, but SCC resistant. Precipitation at grain boundaries is discrete, although the precipitated fraction is greater (3%) than in specimens annealed at 320 8C. Potentiodynamic measurements show that of all measured parameters, charge density is in the strongest correlation with the NAMLT and SSRT results.