Biodiesel has recently received increasing attention because of many advantages such as higher cetane number and flash point compared to diesel fuel. However, corrosion of engine parts exposed to biodiesel or biodiesel-diesel fuel blends is still a critical challenge in the biodiesel industry. In the existing literature, there is still a lack of systematic studies including corrosion process in light alloy and changes in mechanical and fuel properties of engine parts (such as brass) after exposure to biodiesel. Therefore, in this study, (1) waste sunflower oil biodiesel (WSOB, B100) was supplied and blended with diesel fuel (B0) at the volume ratios of 10%, 20%, and 40, which are called as B10, B20, and B40, as usual. The important fuel properties of the biodiesel-diesel fuel blends were also analyzed using ASTM test methods. (2) Corrosion characteristics of brass exposed to the biodiesel-diesel fuel blends were determined by means of a static immersion method at room temperature. (3) Mechanical properties of brass were investigated before and after the corrosion test. Finally, (4) variations in surface morphologies of the brass coupons were researched. According to the experimental results, the corrosion rate (0.3810 mpy) of brass exposed to B100 was found to be higher than that of brass exposed to B0 (0.1330 mpy) for the exposure duration of 960 hours. The Brinell hardness numbers (BHN) were determined as 406.265, 477.713, 541.983, 579.448, and 636.602 N/mm(2) while the tensile strengths (TS) were 1381.30, 1624.22, 1842.743, 1970.13, and 2164.45 MPa for B0, B10, B20, B40, and B100, respectively. BHN and TS values of B10 were closer to that of B0. Therefore, B10 was found to be a more suitable alternative to diesel fuel in terms of fuel property and corrosion characteristic. The results of this study can promote thermo-physical property collection for biofuels and guide for corrosion studies related to the industrial applications of diesel-biodiesel blends and pure biodiesel.