Corrosion fatigue (CF) behavior has been investigated for an austempered ductile iron (ADI) by conducting systematic fatigue tests at 20 Hz, including both high-cycle fatigue (HCF, S-N curves) and fatigue crack growth (FCG, da/dN-DeltaK curves), in air, lubrication oil and several aqueous environments. Results showed the HCF resistance of ADI was dramatically reduced by the given aqueous media, in particular, to a greater extent with a decrease in pH value. However, the given room-temperature aqueous solutions did not exert significantly detrimental effects on the Stage II crack growth compared with an atmospheric environment but an increase in solution temperature caused enhanced Stage II crack growth. Among the given variables of the bulk environment, pH had the greatest influence on HCF response while temperature had the most influence on the FCG of long cracks. In addition, SAE 10W40 lubrication oil provided an inert environment to remove the corrosive effect and enhance the CF resistance of ADI. The overall comparisons indicated the environmental effects would generate more influence on Stage I cracking than on Stage II cracking for the given ADI. (C) 2003 Kluwer Academic Publishers.