Microorganisms associated with accelerated corrosion processes are often identified through culturing of specific kinds of organisms and evidence of certain chemical processes; however there is growing evidence that diverse microbiological communities are at the heart of microbiologically influenced corrosion as opposed to only "healthy populations of certain problematic microorganisms". Emerging molecular methods based on the analysis of DNA extracted from field samples provide a new opportunity to characterize microbial populations associated with corrosion problems in the oil and gas industry. This paper reports the application of these methods to samples obtained from the excavation of external corrosion sites under disbonded coating on an operating transmission pipeline. Insights into the nature of the microbial communities associated with corrosion products trapped water coating and soil will be presented along with comments on the potential of this approach for future investigations.