The sulphate-reducing bacteria (SRB) are the most serious culprits among the bacteria often implicated in deterioration of petroleum products and production facilities. Sulphate-reducing bacteria promote sulphidogenesis under favourable environmental conditions. This can occur in oil and gas installations such as pipelines, storage tanks, cooling circuits, production wells, injections wells and reservoirs. Biogenic sulphide produced by SRB can cause souring and biocorrosion, which is costly to mitigate. This book discussed the microorganisms associated with souring and corrosion, the mechanisms involved and mitigation strategies, special emphasis was given to control of the activities of SRB using fungal sporocarp and plant extracts. The discussions and results presented in this book should be especially useful to professionals in the field of petroleum microbiology and anyone interested in biocorrosion.