The effect of sulfate ions on the crack growth rates (CGRs) of notched specimens (CT) of Inconel 600 under constant load has been investigated in chloride containing aqueous solutions at 250 degreesC. The intergranular stress corrosion crack growth rates increased in chloride solutions while its hinder with increasing sulfate concentrations. Stress intensity factor (k) for stress corrosion cracking decreased with increasing of aggressivity of chloride ions while increased in the presence of sulfate solutions. At very low concentration of chloride (0.001 m), k-value retardation was observed. It is clear from the results that hydrogen in the aqueous solutions has a deleterious effect on crack propagation. The difference in crack growth rates in chloride ions and in chloride containing sulfate solution at high temperature can be recognized as caused by the difference in local environment conditions at a crack tip. The results indicate that the crack don't propagate under this conditions in the presence of sulfate ions. It is mainly due to a hinderance of chloride ions adsorption on active sites of the fracture surfaces and the formation of chromium oxide layer which is stable at higher temperature.