A model has been developed to improve microbiologically influenced corrosion (MIC) assessment and direct mitigation for upstream production and transport facilities. This model leverages previous MIC modeling activities with attention to increasing delineation of predicted MIC probability incorporating practical field experience considering data from advanced bio-monitoring techniques and assessing MIC risk. The input parameters for the model are of two different types; prediction factors and monitoring factors. These two types of factors are treated by two different mathematical operations. The probability of MIC for a given system is provided as an index as well as a semi-quantitative probability class. The MIC Risk is based on the Probability of MIC combined with the Consequence of Failure (COF) due to an internal corrosion failure. The risk assessment component of the model recommends general surveillance bio-monitoring and/or mitigation for both design and operating scenarios based on the results of the MIC risk assessment.