Many of the crude oil producing wells operated by the Kuwait Oil Company (KOC) have been operating for many years and the natural pressures in these wells have gradually diminished resulting in decreased production. In such cases the Company has started using secondary oil recovery methods such as seawater and effluent water injection gas lifts and electrical submersible pumps. Utilization of water injection entails the careful control of total suspended solids (TSS) dissolved oxygen (DO) and bacteria in the seawater and effluent water systems. The DO content should be kept below 40 ppb (parts per billion) and the bacteria population particularly sulfate reducing bacteria (SRB) should be ideally zero. However excursions in these parameters do occur and can result in oxygen corrosion or microbiologically influenced corrosion (MIC). Bacteria can also lead to potential souring of the formation.The present paper discusses the characteristics of corrosion damage that has been observed in the seawater and effluent water injection systems operated by KOC. In both cases the enhanced corrosion observed on coupons could be attributed to oxygen ingress or the presence of bacteria. The two types of corrosion damage could be distinguished based on the unique corrosion morphological features in each case.Key words: Corrosion Morphology MIC Oxygen Corrosion