AISI 304 type stainless steel is widely used in engineering applications due to its high corrosion resistance associated with Cr addition. Many stainless steels structures such as pipes and pressure vessels are subject to fatigue loading during service operation. The main objective of this research is to investigate the effect of loading frequency on the kinetics of fatigue crack propagation of 304 stainless steel exposed to 3.5% NaCl solution. Two microstructures are examined: annealed and sensitized 304 stainless steels. Sensitization is known to reduce the corrosion resistance of stainless steels and lead to intergranular corrosion. Sensitization is performed at 680°C for 8 hours. Fatigue testing will be carried out according to ASTM E-647 standard using a compact testing type (CT) specimen. The results of this study will be presented with emphasis on the role of sensitization on the cracking processes of stainless steels.