Abstract: The notch effect on high temperature LCF (Low Cycle Fatigue) and fatigue/creep interaction behaviour was investigated in GH33A super-alloy. LCF life was decreased dramatically because of notch and acuity of notchs. During LCF tests, dwelling at maximum stress introduces creep damage into low cycle fatigue, then decreased LCF fatigue cycles. At LCF tests with constant maximum stress and varied minimun stress, fatigue/creep interaction curve exhibits a maximum fatigue life at certain stress condition and fracture character can be gradually changed from pure fatigue into pure creep with increasing in mean stresses and decreasing in alternating stress amplitudes.