The corrosion resistance of two aluminium alloys, 6063 and 3003, has been compared using a 0.5 M sodium chloride solution. The results obtained with electrochemical and metallographic techniques show that alloy 6063 is more resistant than alloy 3003 at 25°C. The corrosion rate tends to increase as the pH deviates from neutrality. When the chloride concentration is decreased, the resistance to pitting corrosion is improved for both alloys. The influence of the temperature of the medium on the behaviour of the two alloys has also been studied. In the case of alloy 3003, the corrosion rate (Icor) increases with temperature up to 55°C, but drops back to its room temperature value at 65°C. In the case of alloy 6063, Icor decreases as temperature is raised up to 65°C. At all testing temperatures, the 6063 alloy has a better corrosion resistance than the 3003 alloy.