The tribological behavior of cast iron was investigated by sliding a disk against a bearing steel pin in ethanol, with and without oleic acid, using a pin-on-disk machine. The addition of oleic acid resulted in decreased friction in ethanol. The profile of the wear track was measured using a surface texture and contour measurement instrument. Microstructural observations and chemical analysis of the worn surface were performed using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS), respectively. The results indicated that mechanical wear such as plowing and adhesion occurred on the sliding surface of the cast iron in ethanol. In addition, galvanic corrosion was identified as a possible main cause for the removal of the cast iron material by sliding in ethanol with oleic acid.