The corrosion behaviour of brass (Br), galvanized steel (GS) and stainless steel (SS) on exposure to Jatropha biodiesel and its blend with petroleum–based diesel was investigated in this study. Jatropha biodiesel was produced via transesterification reaction with methanol using sodium hydroxide as catalyst. Corrosion rates of these metals were evaluated using weight loss method after the metals were immersed in the fuels for 8 weeks. The acid value (AV), peroxide value (PV) and iodine value (IV) of the fuels during the immersion test were analysed. The degradation of the metal surfaces and the colour of the biodiesel fuel at the end of the immersion test were also characterized by visual inspection. The corrosion rate of Br, GS and SS in Jatropha biodiesel after 8 weeks (56 days) of exposure was 0.6091, 0.3435 and 0.053 mpy respectively. As the volume of diesel was increased in the blend, the corrosion rates of the alloys decreased. There was increase in both the AV and PV during the immersion test with the fuel containing Br having the highest value. A decrease was observed in the IV of the Jatropha biodiesel during the immersion period. Changes in colour were also observed for the biodiesel containing the metals.