W e have studied t h e behaviour of an A1-Li alloy (8090) t o p i t t i n g corrosion and exfol i a t i o n a s a function of ageing temperature. Three methods have been employed : I ) visual estimation using EXCO-test (ASTM recommandations), 2) potenti a1 -solution 1 eve1 measurements i n EXCO, CH30HICC14, CH30H/CC14/CuC12 and NaC1 /Hz02 solutions, 3) s t r e s s corrosion cracking by slow s t r a i n r a t e method. Correlation has been found between these methods, especi a1 1 y i n t h e ageing temperatures range 125O t o 190°C.