Microbiologically influenced corrosion (MIC) is recognized as a considerable threat to carbon steel asset integrity in the oil and gas industry. There is an immediate need for reliable and broadly applicable methods for detection and monitoring of MIC. Proteins associated with microbial metabolisms involved in MIC could serve as useful biomarkers for MIC diagnosis and monitoring. A proteomic study was conducted using a lithotrophically-grown bacteria Desulfovibrio ferrophilus strain IS5, which is known to cause severe electric MIC in seawater environments. Unique proteins, which are differentially and uniquely expressed during severe microbial corrosion by strain IS5, were identified. This includes the detection of a multi-heme cytochrome protein predicted to be involved in extracellular electron transfer in the presence of the carbon steel. Thus, we conclude that newly identified protein biomarker for MIC could be used to generate easy-to-implement immunoassays for reliable detection of microbiological corrosion in the field.