Résumé : Microbial influenced corrosion (MIC) is one of the major concerns in industries due to huge economic losses. Sulfate-reducing bacteria (SRB) are well studied and highly corrosive in nature. However, the MIC mechanism, especially by iron-oxidizing bacteria (IOB) is not yet elucidated. In this context, this study presented the co-relation of extra polymeric substances (EPS) exuded by IOB strains as a key mechanism for MIC of mild steel. Herein, the corrosion behavior of mild steel influenced by EPS of two IOB strains; DASEWM1 and DASEWM2 isolated from river water was investigated. Comparative studies using surface analysis, electrochemical tests and immersion tests in nutrient broth media revealed a higher degree of corrosion in inoculated media (strain DASEWM1 < DASEWM2) than control media. These results were also supported by EIS and FESEM of corroded steel surfaces. Moreover, electrochemical and EPS constituent’s analysis, the correlation between the corrosion rate to the EPS constituents were also studied.