Ethanol-gasoline blends (EGBs) can easily absorb large amounts of water because of the presence of ethanol. Acidic compounds and ions can be dissolved in water, and these substances can have corrosive effects on metallic construction materials. With the increasing content of ethanol in fuels, the conductivity and ability of fuel to absorb water increases, and the resulting fuel is becoming more corrosive. In this work, we tested E10, E40, E60, E85, and E100 fuels that were prepared in the laboratory. These fuels were purposely contaminated with water and trace amounts of ions and acidic substances. The aim of the contamination was to simulate the pollution of fuels, which can arise from the raw materials or from the failure to comply with good manufacturing, storage, and transportation conditions. The corrosion properties of these fuels were tested on steel, copper, aluminum, and brass using electrochemical impedance spectroscopy and Tafel curve analysis. For comparison, static immersion tests on steel were also performed. The main parameters for the comparison of the corrosion effects of the tested fuels were the instantaneous corrosion rate; the polarization resistance; and the corrosion rate, which was obtained from the weight loss occurring during the static tests. In most cases, E60 fuel showed the highest corrosion activity.