This paper presents a case study of ASME SA213 type-T22 alloy steel superheater tube that failed in a boiler of a power plant. The failed superheater tube was investigated by visual examination, metallography, optical microscopy, electron fractography, and hardness testing. Microscopic examinations revealed inclusion, pre-existing micro-cracks and cementite precipitates at the grain boundaries in the microstructure; which were thought to be one of the major causes of failure of the superheater tube. Another major cause failure of boiler type T-22 was found to be creep failure because the boiler had been under use for a long time (36573 hours) at high steam temperature of around 420 °C with 130 bar pressure. Finally, recommendations have been suggested to improve the material characteristics and properties of the superheater tube for application in boiler of the power plant.