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Microbiologically‐influenced corrosion (MIC) is extremely harmful to both the industry and the environment. Sulfate‐reducing bacteria (SRB) are also important: we have to know what they really are and what they really do to us; this means we have to improve our understanding of SRB and their characteristics. MIC is the officially accepted terminology by NACE[1] to address this type of corrosion. It is a kind of corrosion in which effects of certain microorganisms are felt. MIC is still a matter open for discussion: we cannot explain what is really meant by “microbiological” component, i.e. does it express the possibility that some microbial activity observed at corroded sites on metal surfaces may not result from bacterial growth on metal, but rather that chemical or electrochemical attack on the metal may provide a favorable niche for bacteria to grow? Nor can we be sure about our understanding of the importance of working mechanisms and even the types of microorganisms involved in MIC. In order to have a deeper understanding about corrosion caused by sulfate‐reducing bacteria (SRB), we have to know more about SRB themselves. So, after discussing the importance of MIC, we will mainly focus on SRB and their characteristics that may be new and interesting to the reader.

Corrosion management principles, along with conventional technical solutions to corrosion problems in industry, can be utilized to mitigate corrosion and its resulting problems.

Microbiologically Influenced Corrosion (MIC) is an electrochemical corrosion influenced by the presence/action of biological agents such as, but not limited to, bacteria. One of the key elements of MIC is sulphate-reducing bacteria (SRB). There are still many misunderstandings about these bacteria, their role in the deterioration of engineering materials and their importance over other types of corrosion-related micro-/macro-organisms. SRB do not require oxygen, yet they can be found in oxygenated environments; they are capable of tolerating a relative wide range of temperature, pH, chloride concentration and pressure values. Not only can SRB have deteriorating impact on engineering materials, they are also capable of inducing harm to health and agriculture. In this paper, after reviewing facts and figures regarding ecological and economical impacts of corrosion in general and MIC, in particular, the central concept of MIC, that is, biofilm formation and its deterioration mechanisms and the role of SRB in such mechanisms are described. Also, the possible enhancing role of SRB on stress corrosion cracking of steels and the controversial concept of no relationship between the number of SRB and corrosion rate are addressed and reviewed.