Metal corrosion resulting from microbial processes constitutes a serious expense in many industrial applications. Oil pipelines are plagued by these events leading not only to economic losses but also severe environmental consequences. Therefore, our understanding of the microorganisms that contribute to metal corrosion is vital. Here, the roles of a methanogen and either a sulfate-reducing bacterium or archaeon in corrosion are addressed. The methanogen Methanothermobacter thermautotrophicus was used to assess the effect of methanogenesis in corrosion. The sulfate-reducing bacterium Desulfomicrobium thermophilum and the sulfate-reducing archaeon Archaeoglobus fulgidus were used to measure the effect of sulfate reduction on corrosion. To assess the combined effect of sulfate-reduction and methanogenesis on corrosion, M. thermautotrophicus was grown in combination with A. fulgidus or D. thermophilum. This allowed investigation of corrosion impact at different temperatures and salinities. All organisms contributed to corrosion, measured by metal weight loss over time, either independently or in conjunction with a partner organism. Corrosion resulting from strictly biotic processes was dominant at lower temperature and salinities. At higher salinities and temperatures, approximately half of the corrosion measured was because of abiotic reactions as indicated by experimental controls. This work demonstrates the role of these microbial metabolisms in metal corrosion in anaerobic environments.