For the last 30 years, reformer tubes are gone through numerous changes in manufacturing processes and material of construction to improve performance and reliability. To increase plant through-out Qatar Fertilizer Company replaced the old HK40 tubes with HP modified alloy but within 24 months of operation, unexpected corrosion attack was observed on some of the reformer tubes. In this article, the potential root cause of the tube damage and remediation actions has been discussed. (C) 2011 American Institute of Chemical Engineers Process Saf Prog 30: 157-163, 2011